Talk:24-hour clock/Archive 1

My edit: Removed 'clip card'-picture
I removed the picture of the danish 'clip card', which was irrelevant for the article. It was shown as a non-standard time example, which it is not.

The clip card has the clockformat it has, because the danish buses start driving at 05 AM. After 12 PM until 5 PM, there is nightbusses. So when it says '27:45' it means 24 - 27 = 4:45 AM.

This has something to do with the national traincompanys clockformat. I can't quite explain why.

-NNe, Dane. —Preceding unsigned comment added by 90.184.90.152 (talk) 20:45, 16 August 2009 (UTC)

Ancient a.m./pm. system versus 24-hour-clock
Favourably in USA and a few other countries, the a.m p.m system is still in use.

Since SI-System was invented [kg, m, s, 24 h/d for the length of an earth day] fovourably in the USA, and elsewhere, i.e. in NZ, they still stick on the old fashioned a.m./p.m. system.

The landing on the moon by US(!)-astronauts in 1969 was already successfully operated by using kilometres (km) instead of miles, metres instead of feet and a 24-hour-clock. Times were in UTC, former GMT ( but in 24-h-system already).

NASA was later unable to invent the SI System in the US as by SI convention.

Thus, in USA and a few other coutries, the 24-hour-clock is not yet in use. —Preceding unsigned comment added by 79.199.223.99 (talk) 21:58, 31 August 2008 (UTC)

Dateline for the world wide removal of the 12-hour-clock and else
Is there any date predictable/on the horizon of time, on which the 12-hour-clock,

together with fahrenheit, ounces, barrels, gallons, kph (instead of km/h), mph, miles and more...,

are to be removed, from international pages on the internet at least?

Why more than 200 countries must wait until the last three stuck to the past, "non-metrics" Burma, Liberia and U.S.A., will become aquainted with the 12-h-system and the metric system?

79.199.251.95 (talk) 14:39, 1 August 2008 (UTC)kpkp_de@yahoo.de79.199.251.95 (talk) 14:39, 1 August 2008 (UTC)


 * Change is hard. People often have an "intuitive" sense for units. Somebody who can accurately estimate how big something is in feet by looking at it would be lost if they everybody started using a different unit. In addition, the US has a somewhat "rebellious" attitude towards European countries. We like doing things differently. There is no "horizon of time" coming, as we are not a part of any organization that requires that metric units be used. There may be some hope for the 24 hour clock, though: One of the US's largest organizations, the military, uses the 24 hour clock exclusively. —CobraA1 23:01, 24 February 2009 (UTC)

Analog 24-hour clocks
There are analog clocks and analog watches that display the time using the 24 hour clock. In fact, ever since the very first clock face was designed, there have been 24 hour analog clocks. Harrison's H1 chronometer, for example, has a 24 hour analog dial. After about 1500 to 1600 CE. this type of dial was used primarily for scientific and technical use.

Pete Boardman
 * Yes there are. Also there are clocks that chime for the whole 24 hours. I would assume they would chime 24 times for 00:00 rather than nothing at all. Borb 10:55, 13 August 2005 (UTC)

24:00
Reason for my edits:

the day begins at midnight, 00:00 (12:00 am), and ends at 23:59:59 There is no 24:00

Not strictly true: 24:00 (otherwise 24.00, 2400, etc.) is frequently used, for example in railway timetables, to denote the end of the day. A train due to arrive at a station during the last minute of the day is shown as doing so at 24.00; a train due to depart during the first minute of the day is shown as doing so at 0.00. -- Picapica 16:54, 2 Oct 2004 (UTC)

I thought of adding a note on alternative notations: 1234, 12.34, etc. for 12:34 - but perhaps this would be needlessly confusing? -- Picapica 17:22, 2 Oct 2004 (UTC)


 * I have sympathy for keeping the notations restricted to the hh:mm and hhmm styles. These are the ones defined in ISO 8601. Of the others, only the one lacking the leading zero for the hour is widely used (now also mentioned). The problem with hh.mm (the old official German DIN 1355 notation, before it was replaced by ISO 8601 in the mid 1990s) is that it is easily confused with a decimal fraction, and the fact that ISO 8601 also allows decimal fractions of hours (e.g., 10.50 = 10:30). So the colon is a good reminder that this is a base-60 notation, whereas dot and comma indicate base-10 notations. Markus Kuhn 14:00, 19 Jun 2005 (UTC)

Isn't the last minute of the day 23:59? 24:00 would be exactly the same time as 00:00 on the following day? It is interesting to me that the train time-tables use both 00:00 and 24:00.


 * Train time-tables used to avoid 00:00 altogether in order to reduce confusion. That may have changed, of course. --Palnatoke 09:33, 9 Nov 2004 (UTC)

I've never seen 24.00 on a railway table, and I have seen 0.00 on a tram table. The times were on a "stem-and-leaf" type table, and it would look out of place to have a "24" hour with just one entry. However, "0-24" is common to indicate 24 hours; one subtracts the left number from the right and gets 24. Also, wrap-around is common, e.g. a restaurant might say 10-03; as an American, I remember being initially confused by that in Europe... I was at a restaurant at 9pm and was surprised it was open. EventHorizon talk 05:55, 8 Feb 2005 (UTC)


 * I've never seen 24:00 on a railway timetable either. On a side note, further down the article (unrelated to the section about timetables) it says midnight is "24:00", surely it's 00:00. -- Joolz 22:31, 19 Mar 2005 (UTC)
 * I noticed the other day that my kitchen cooker goes to 24:00. -- Joolz 22:24, 2 Apr 2005 (UTC)


 * And then the cooker clock moves on to 00:01?, just curious &minus;Woodstone 21:00, 2005 Apr 3 (UTC).


 * Yeah, I found it weird too. -- Joolz 00:32, 4 Apr 2005 (UTC)

I just checked my railway table and it has occurrences of both 00:00 and 24:00. Since midnight is the boundary between two days, it can be expressed as the end of one day or the beginning of the next. &minus;Woodstone 23:48, 2005 Mar 19 (UTC)

Not sure about mentioning both 00:00 and 24:00 in the bullets at the bottom: we just mentioned digital watches above, and none of them show 24:00. I've only ever seen 00:00: I think 24:00 is pretty rare and only used in certain cases such as the trains. Turnstep 20:31, Apr 8, 2005 (UTC)


 * Both 00:00 and 24:00 are part of the ISO standard defining the international notation of date and time, so it makes sense to mention both. If I might guess, I think seeing 23:58 in print is more rare than 24:00. Of course I did not expect ever to see it on a clock (such as Joolz's cooker). A clock has to make a choice and surely 00:00 makes more sense, since it would stay displayed till 00:00:59. &minus;Woodstone 20:50, 2005 Apr 8 (UTC)

I've added a picture of the cooker showing the time 24:00, unfortuantly it's quite low quality. I'll try and replace in a few days with a high quality one. -- Joolz 00:20, 9 Apr 2005 (UTC)
 * Replaced :> (OK, a bit longer than a few days, but still.) -- Joolz 20:10, 8 Jun 2005 (UTC)
 * I changed your caption to clarify that this image shows a curiosity and not the standard behaviour of most digital clocks, which count from 00:00 to 23:59 such that the wrap-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date. Markus Kuhn 14:00, 19 Jun 2005 (UTC)
 * I recommend removing this image. As stated above, this is just an aberration, and will likely just confuse someone taking a cursory look at this article to learn about 24 hour clock. -Froese 06:47, 21 January 2006 (UTC)

In the military, I thought they just used the notation 0023 for example, not using the colon. I assume this is becasue when they talk over radio they would simply say four figures for the time like "zero zero two three hours". Borb 11:03, 13 August 2005 (UTC)

How is 24:00 different then 00:00? 24.237.198.91 10:26, 9 April 2006 (UTC)


 * For the same date 24:00 is 24 hours later than 00:00. So opening hours on a date could be 00:00 to 24:00. Stated otherwise 24:00 on one date is equal to 00:00 on the next date. &minus;Woodstone 11:31, 9 April 2006 (UTC)

The January 2008 version of the London Underground map says that on the Woodford to Hainault section of the Central Line, "services run until 2400" (note no colon, as is standard in the UK transport industry). This is a use of 24:00 to mean midnight at the end of a day (and because people would be confused if it said 0000). &minus; 3 February 2008, 16:24 (UTC) —Preceding unsigned comment added by 195.92.67.74 (talk)

Usage by region/country/culture
I have moved all country-specific discussion into a separate section. I believe this is the only part of the article that still needs substantial work. Markus Kuhn 14:00, 19 June 2005 (UTC)

Leading zero for hours up to 9
The article was modified to state that a leading zero for hours up to 9 is not mandatory. That would then be the only place where leading zeroes are not mandatory (month, day, second must still have fixed number of digits). If the statement is true the advantage of easy (character based) sorting of date/time is lost. Can you elaborate? &minus;Woodstone 19:25, 2005 Jun 19 (UTC)


 * Leading zeros are clearly not optional in the ISO 8601 notation (and probably also not in the U.S. military-style colon-free "hhmm hours" notation). However, this article is about the use of the 24-hour notation in general and not only about the ISO 8601 version of it, for which there is a separate article. The majority of people in regions where the 24-hour clock is the standard colloquial way of writing a date would certainly write "9:00" instead of "09:00". Most digital wrist watches in 24-hour mode show "9:00" instead of "09:00". I think this is plenty of evidence to support that using a leading zero for hours is not something strictly required for use with the 24-hour notation. It is only required by specific computer data formats, such as ISO 8601. Markus Kuhn 13:12, 18 July 2005 (UTC)

Make the Windows clock show military time?
Are there any freeware programs that can make the Windows clock on the taskbar display in military time? I looked on Google and couldn't find any. --pile0nadestalk 22:50, 17 July 2005 (UTC)
 * I've no idea, mine is set to display the 24-hour clock, and I haven't used any third party programs to do it (nor could I find the option in Windows either), you would be better off trying WP:RD for your answer. -- Joolz 00:15, 18 July 2005 (UTC)
 * Thanks, but I already did. --pile0nadestalk 00:46, 18 July 2005 (UTC)
 * I've had another look, and I've found it. If you're using XP, go to the control panel, look in "Regional and language options", click customize, choose the time tag, and use uppercase Hs. Hope this helps, Joolz 01:12, 18 July 2005 (UTC)
 * Good idea! I've added a brief section on this to the article. Markus Kuhn 13:56, 18 July 2005 (UTC)

It might be a good idea to include how to do it on other OSes like Mac OS X and Linux --pile0nadestalk 07:18, 31 July 2005 (UTC)
 * Windows shows military time by default if you select nationality as UK. It uses 12 hour if you select US. Its because a lot of americans don't know what a 24 hour clock was, and that reminds me of an anecdote. I was talking to an american once and I said "its 23:00 here, whats the time there?" and he was really confused. When I finally managed to explain 24 hour clocks he said "we have a much simpler system here, it uses only 12 hours and am and pm." lol. Borb 10:59, 13 August 2005 (UTC)

To change to the 24 hour clock in Windows XP go to Settings->Control panel->regional and language options. click on customize. Then pick the time tab. You will see a note on the bottom of the window concerning 24 hour time. just enter the time format as HH:MM:ss and presto it is now in 24 hour format.--stickman 01:18, 15 November 2005 (UTC)

Usage in UK
Is there a source for the paragraph about usage in UK where it says its not as universally used as other countries? I would say that every digital clock in my house uses either 24 hour by default or at least an option. All major news networks use 24 hour notation including BBC and Sky News. Teletext and Ceefax use it. I certainly use it if I can and I don't think any one doesn't understand it like a lot of people in USA (see my anectode earler on this page). I think what is said may be true but only half of the truth, it makes it sound like USA use 24 hour clocks more than UK which is not true. Borb 11:15, 13 August 2005 (UTC)


 * I've just rephrased both the US and UK usage paragraphs. Better now? Markus Kuhn 18:04, 13 August 2005 (UTC)


 * Yes, that's much better, thanks. Borb 13:51, 14 August 2005 (UTC)


 * Your droll little anecdote aside (who knew that a sample of 1 is statistically significant for a population of 300 million!), I note that The Guardian's website for breaking UK news identifes the time of its last update with 12-hour clock notation. As does The Times's cinema listings. But maybe these aren't major news outlets? 64.198.252.184 04:16, 22 January 2006 (UTC)


 * Not any more. Guardian website uses 24 hour time now. Things have moved on in three years. Mesdale (talk) 15:28, 13 November 2009 (UTC)

Your example for spoken times (eg Birmingham) could usefully mention how times with hours 12 - 24 and no minutes are spoken. Perhaps more examples, eg from the BBC World Service, might be useful. "It's 3 hours, GMT". "The time is 17 hours, GMT, here in London". Cormullion 22:05, 28 March 2006 (UTC)

At Birmingham New Street, or for that matter any other National Rail station in the UK, you will find that no trains are scheduled to leave at 24:00/00:00 ever. If a train were to be at any station at midnight, it would be advertised as arriving at 23:59 and departing at 00:01. Pimpmytrain 05:05, 27 April 2006 (UTC)

I think more and better examples would be nice for UK spoken english. People don't speak like a robotic Birmingham New Street computer. People don't say "oh six fifty-nine", they say "six fifty-nine". People don't say "oh seven hundred hours", they say "seven o'clock", even if the same person would go on to say "seven oh one". --squish 00:20, 17 June 2006 (UTC)

I agree. I live in Birmingham and you would never ever hear the time announced as 'oh six fifty-nine'. Who on earth wrote that? —Preceding unsigned comment added by 129.67.49.146 (talk) 01:41, 5 October 2007 (UTC)


 * Perhaps it could be said as "Cinemas, Buses, Trains, etc etc in the UK use 24 hour time (But not TV and radio usually), but people don't! It's like the haphazard application of the metric system, you drive 5 miles to buy a kilogram of apples! Felneymike (talk) 18:06, 29 February 2008 (UTC)

Windows XP will use 24 hours time format when system locale set to United Kingdom, I removed UK from the list of English locales that use the 12 hour format. Rayrob 14:09, 10 March 2009 (UTC)

Ambiguity
"The 24-hour clock enjoys broad everyday civilian usage in most Asian, European and Latin American countries, where it is almost exclusively used to write down times." -- This can mean that when writing down times it is almost always used, or it can mean that it is rarely used except when writing down times. (Actually, in Japan AM and PM are nearly always used except for some things like train timetables.) --Zero 14:16, 14 August 2005 (UTC)

"In written English, there is no conventional notation for indicating that a time uses the 24-hour clock. Therefore, any 24-hour time between 1:00 and 12:59 is ambiguous."
 * I disagree. 1:00 is distinguished as 12-hour because there is no preceding zero. 12:59 can only be 12-hour. It's only the times 10:00 to 11:59 that could be either. But, because in England 12-hour times are written with a pm or am afterwards, I think it is quite clear.


 * I think the ambiguity is there in interpretation rather than implementation. For example, if someone handed you a note saying "Please meet me here at 8:00 tomorrow", you would have no way of knowing whether it was for breakfast or for an evening out. The presence or absence of a preceding zero doesn't really help (see the railway timetable in the article, for example): you don't know whether the writer has omitted the am/pm suffix from a 12h time or has omitted the leading zero from a 24h time. And while 12h-time users can add a am/pm suffix, 24h-time users can't add anything to 10:00 to say "this is 24h time". So writers can specify time unambiguously, but readers can't... That's my theory anyway :-) Cormullion 13:31, 3 February 2007 (UTC)

Potential problem
I find a potential problem with this article in that it seems like it is trying to say the the United States is all alone in its use of the twelve-hour clock system. While the article has a few exceptions to this, I think that it should be made clearer that other large countries still widely use the twelve-hour system. For instance, I have traveled to Canada before, and just about every where I've traveled in that country, the 12-hour system was in wide usage. The only exception to this that I could find was in the province of Quebec, where a modified twenty-four hour system is used. Times are written as, for instance, 18h03 rather than 18:03. This comes from Quebec's use of the French language. The h in 18h03 comes from the French word "heures" for "hours". I have also heard that Portugal follows this same format (where the h stands for "horas", the Portuguese word for "hours". However, I have also heard that Portugal only uses this format on a formal basis (like for trains and shows), and that the twelve-hour system is still used for many informal events and for verbally.

I agree. Not only that, but both here, and at the 12-hour clock page, the U.S. seems to be criticized for using the 12 hour system. No offense, but just because Europe jumps on the bandwagon, that dosne't mean we should too. That's what's so great about individuality. Pacific Coast Highway 05:47, 2 October 2005 (UTC)


 * I can't find any overt "criticism" of the United States in the current article. The article does explain in great detail the practical advantages of the 24 hour clock, and it does point out that the United States are rather unique in avoiding to expose the general population to it. While it is always difficult to criticise a convention, without implying criticism of its followers, to me the article seems to be a factually pretty accurate and adequate description of the current situation. If not, can you name any other industrialized country where the 12-hour clock notation is used equally universally, even on airline tickets and train timetables, or where a substantial fraction of the population is not even familiar with the 24-hour notation? Can you name any particular advantages of the 12-hour notation over the 24-hour alternative, that can help to explain and justify its continued almost exclusive use in the United States? Markus Kuhn 22:08, 4 December 2005 (UTC)


 * If you reread the first post in this section, you'll find that Canada, still an industrialized country as far as I know, also uses the 12-hour system. As do, according to the partner article at 12-hour clock, Greece and parts of South America.


 * I have to add, that in Argentina and some other latinamerican countries, the 24 hours system is used entirely, for formal dates, programs, calendars, etc, even notations. But when spoken people almost exclusively say "four in the afternoon" for 16:00.


 * As to advantages, the vaunted benefit of being able to avoid confusion over whether "12:00 p.m." stands for noon or midnight is perhaps dispelled by the remarks above regarding the uncertainty over whether midnight is correctly denoted "00:00" or "24:00."


 * I'd also point out that characterizing the situation as one in which the U.S. "[avoids exposing] the general population to [the 24-hour clock]" is not quite accurate, and perhaps smacks of patronizing. There is no conscious effort to spare Americans the difficulty of learning a new system, we simply use a different one. You know, the same way Germany "avoids exposing" Germans to avoirdupois pounds.


 * But I'll make you this deal: if you Continentals give up your fetish for grammatical gender, I'll personally see to it that every American abjures the hopelessly primitive 12-hour clock and its attendent burden of remembering that "12 p.m." is noon and "12 a.m." is midnight.


 * That is the main problem for me with the 12 hour clock, never been able to be really sure which 12pm/am is the 00:00 and which the 12:00


 * Lastly, I register an exception to asserting that most, or even a considerable plurality of, Americans are unfamiliar or unpracticed with the 24-hour clock. Care to provide some substantiation for the claim?


 * 64.198.252.184 03:35, 22 January 2006 (UTC)

Psychological effects?
The "Psychological effects" section sounds dubious to me. Is this just the contributor's personal impression, or a well-documented phenomenon? Only the latter belongs into this encyclopedia. Unless someone can provide solid references, preferably to peer-reviewed scientific literature, that documents the claimed effect, I suggest to remove this entire section. Markus Kuhn 22:08, 4 December 2005 (UTC)

Now moved to talk page until someone can provide a reference. Markus Kuhn 16:38, 28 January 2006 (UTC)


 * "It has been suggested that the 24-hour clock, when contrasted to the 12-hour clock, has certain psychological effects in how the dual-system mind interprets it in accordance to the environment. Mainly found in countries such as the United Kingdom where the two systems lie side-by-side, it has been suggested that reading a time such as 3pm seems earlier in the day than 15:00. The reason for this can be explained in the way the mind interprets time. Whereas 3pm seems to suggest that there is a significant amount of time following it, and is early in the afternoon, 15:00 suggests that it is heading towards the end of the day, therefore making it appear later. This effect can be better demonstrated by changing one's own (digital) watch from 24-hour to 12-hour (or vice-versa) and interpreting the effects oneself."

24:00:00
Does really rarely happen in the instance of a leap second having to be inserted into a year.

This usually happens at midnight and so an extra second is added making 24:00:00.00 before the standard roll over to 00:00:00.00


 * No, as mentioned in the article, the correct notation for a positive leap second is 23:59:60 (see also leap second). Alureiter 02:06, 19 January 2006 (UTC)


 * No, also because 24:00:00 is the same instant as 00:00:00 the next day, so that couldn't constitute a leap second. Thirty years ago I was in the US Army in a time-synchronized occupation. Back then the digital clocks, fed by a digital stream that "ticked" every second, ticked from 23:59:59 to 24:00:00 to 00:00:01 and then so on. There was no 00:00:00. The hour "24" was wasted on a single second, and you would have to assume that the first hour which started at 00:00:01 would also include 01:00:00 so that all hours are equal in duration, each one ending only _after_ the clock's hour has rolled over. Fractions of seconds were of no concern so I don't know how they would have been partitioned. The time-punches that were stamped on official documents also showed 24:00:00, which I guess everyone assumed belonged to the prior day. I spent too many nightshifts in these places. -- como 26 November 2008  —Preceding undated comment was added at 16:15, 26 November 2008 (UTC).

With regards to the picture of a clock showing 24:00, it looks more like someone is setting a countdown timer for 24 hours of time rather than trying to depict the actual current time. - fooflington

Japanese Use
I've recently noticed on many TV schedules and train timetables that times are listed between 05:00 and 28:00 - probably in an attempt to cater for those who stay up all night, but I've never seen this usage anywhere else so I don't know if this is a Japan-only thing. Also note that in Japan, AM and PM come before the time, and not after (eg, AM8:00~PM10:00). --PkerUNO 09:55, 2 April 2006 (UTC)

Different separation characters
In Sweden, the land of my fathers, we use a point for separation of hours and minutes, i.e., "12.34". Some Ukranian friends also told me that they usually write "1234". (In neither case I know what happens when it comes to seconds.) The article should probably mention different notation standards and where they are used. I'm afraid I know nothing more than what I have told you already, and don't have any reliable references for backing even that up. Bromskloss 12:46, 24 April 2006 (UTC)


 * In Germany, it used to be the dot as well (DIN 1355, DIN 5008), as in "12.34". The German standards on this were changed (in the case of DIN 5008) in about 1995 to the colon, as in "12:34", in line with how ISO 8601 does it, or replaced by DIN EN 28601 (in the case of DIN 1355). Soon afterwards, the colon started to show up in widely used style guides (e.g., the one in the Duden). The house styles of some individual German publishers might still follow the old (1950s) DIN 1355 time notation with dot; such things take time to catch on. I'd not be surprised if the situation in Sweden (and other European countries) is actually similar, i.e. that the formal standards switched already from dot to colon, but that such a change has not yet caught on universally. Do you have information on current Swedish standards and style guides on the matter? Markus Kuhn 20:22, 24 April 2006 (UTC)

Speach
in English the spelling for 0 is o not oh as stated in the article. sorce THE OXFORD AMERICAN COLLEGE DICTIONARY. Zginder 16:14, 6 May 2006 (UTC)

In English the spelling for "speech" is "speech" not "speach" as stated in the header of this section. source SUCCESSFUL COMPLETION OF THE THIRD GRADE.

How does one pronounce 0001 through 0059? Would one say "oh-oh-oh-one" or "oh-oh-one" or "oh-hundred-one"?

History
One day I'll add some history about this topic. You can find more at 24 hour analog dial at the moment, but I think it would be interesting to have some information about usage over the centuries.


 * The earliest primary source I have traced so far is a manuscript written in about 1350, MS Ashmole 1796. Part of it is reproduced on page 186 of John North's book about Richard of Wallingford "God's Clockmaker". It shows a chart of the numbers 1 to 24, arranged on a grid and showing a how a clock mechanism could be designed to strike the number of hours (1 to 24) without a 300 peg hour striking wheel. So at the moment the first recorded usage of the 24 hour clock is from - England... Cormullion 20:29, 9 May 2006 (UTC)

Neutrality
Does not mention disadvantages only the advantages. I could see how it lest two of the sme points under advantages could be used under disadvantages. Zginder 19:38, 7 May 2006 (UTC)


 * Hi Zginder. I'm sorry to say I did actually delete one of your comments under Disadvantages, but it was the one when you said the 24 hour clock system is French. This is not only untrue, in my opinion (Egyptian or Italian I would accept :-)), but also I don't think you could argue that being French was a disadvantage... I thought that your comment about number bases was true, but I couldn't quite see how relevant it was to the 24 hour system that you can't divide 60 by an integer to get 24. It has some relevance to the design of 24 hour analog dials, but that's another topic... (I didn't delete that one.) As for the two midnights objection, I didn't think that made any sense, although I didn't delete it. There are two midnights, embracing the day, so why not a proper unambiguous notatation for them...?


 * I do, however, agree with you that the sentence "The United States and Canada are the only industrialized countries left in which a substantial fraction of the population is not yet accustomed to it." could be improved to convey a more neutral opinion. It's the use of the phrases "the only industrialized countries left", and "not yet accustomed"... These are plainly loaded phrases, implying "they're lagging behind", "they should know better", and "they need educating", which certainly undermines the article's neutrality. And I'm a 24 hour clock zealot...


 * I think there are some disadvantages, too, but I think these are mainly in the realm of pronouniciation and speech, due to the fact that English is both the world's lingua franca and the least 24-hour-friendly language. Cormullion 17:28, 8 May 2006 (UTC)


 * The article does say it is called continental time in the United Kingdom and there are no English speeking countries on the of mainland Europe. It is French.  The Egyptian had a 12-hour clock. Zginder 19:42, 8 May 2006 (UTC)


 * A leading zero is inefficient. Zginder 19:48, 8 May 2006 (UTC)


 * It is childish to think that there are two midnight in a day. That would mean two points in time with the same name right after one another.  The day begins with midnight.  The day ends right before midnight. Also, it is customary that the time interval associated with a given time display is closed at the start and open at the end. If we accept that convention, then it only makes sense – in the interest of consistency – to also interpret the time intervals denoted by the period of a day as closed at the start and open at the end. In other words, "day" covers the interval [00:00, 24:00) Zginder 22:04, 8 May 2006 (UTC)


 * I really like the last sentence, showing how useful it is to have an expression (24:00) for midnight at the end of the day. &minus;Woodstone 11:12, 9 May 2006 (UTC)


 * I only used the 24-hour clock above because this article is the 24-hour clock. Hah! Your wrong.  Zginder 22:07, 22 July 2006 (UTC)

Consistency between 12-hour clock and 24-hour clock
Can we ensure that there is consistency between 12-hour clock and 24-hour clock? The issues are almost identical but the articles are inconsistent.

Perhaps we should have a single article. bobblewik 07:27, 15 May 2006 (UTC)


 * The overlap is mostly in the "Use by country" section, which was copied recently. I suggest we move that entire section into a separate article date and time notation by country and leave only 2–3 summarizing sentences in the article. Markus Kuhn 13:47, 15 May 2006 (UTC)


 * It was me that copied 'Use by country' in. That was just one area. I don't think we can solve it by pulling sections out one at a time. See 'advantages/disadvantages', 'Typography', 'Criticism'. Content is almost entirely comparative and not unique.


 * I propose a parent article called 'Time formats'. bobblewik 17:57, 15 May 2006 (UTC)


 * No that would change the fact the Americans and Canadians should edit the 12-hour clock and everyone else the 24.  That is how it should be, thou it isn't. Zginder 22:07, 22 July 2006 (UTC)

Australia - Double negative
"It is unlikely that Australia will never migrate to 24-hour notation." What did the author intend to say? I assume it was "...will ever...", but I've nothing to back it up. (unsinged, copied from 12-hour clock by Zginder 13:32, 27 July 2006 (UTC))

Cites for 6 hour clock in other East African languages?
24-hour clock: Found cites for Swahili using a 6 hour clock with the day starting at 0600, but still looking for some of the other "many East African languages" that are claimed, including some spoken in Ethiopia, which is claimed in 12-hour clock. TransUtopian 02:52, 3 August 2006 (UTC)
 * The entire 6-hour clock topic is rather off-topic for this page and should really be moved instead to Date and time notation by country, IMHO. Markus Kuhn 13:43, 3 August 2006 (UTC)
 * Done. I didn't fully realize they're actually on a 12 hour time clock, simply offset by 6 hours from ours. I'm still looking for evidence that other East African languages have this custom as well. TransUtopian 15:13, 3 August 2006 (UTC)

Is 24:00 really that rare?
I saw the picture of the cooker on this article about a year ago, but just recently noticed that my oven does the same thing (how often do you look at your oven at midnight?) It is a Neff oven, so it's probably safe to assume all Neff ovens, at least in that era do the same thing. Neff is a popular make for an oven, and it's in the same group as Bosch and Siemens. Can anyone confirm any other ovens that display this behaviour? -- Borb 23:20, 4 September 2006 (UTC)


 * Exact model number and ROM version? I'm tempted to email them a bug report ... ;-) Markus Kuhn 09:02, 5 September 2006 (UTC)

In MacOS 10.4.8 you can choose from the following formats for hour: 1-12, 01-12, 0-23, 00-23, 0-11, 00-11, 1-24, 01-24. Choosing the last of these will display midnight as 24:00, and continue using 24 up to 24:59... Perhaps it's for compatibility with late-night cooking sessions... Cormullion 09:48, 18 October 2006 (UTC)

My cooker does the same. I know it's not Neff, but I can't recall the make (not whilst I'm at work anyway). Definitely displays 24:00 for one minute at midnight before changing to 00:01. It never displays 00:00. Perhaps the part in the article that says "Digital clocks run from 00:00 to 23:59; this means they never show 24:00 on their display. This way, the roll-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date." should be changed to read something like "Most Digital clocks run from 00:00 to 23:59; meaning they never show 24:00 on their display (although some instances that do show 24:00 have been found, for example, on common brands of cookers, where the 00:00 is not displayed). This way, the roll-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date." GC.


 * Just speculation here, but perhaps this is because 00:00 is used to indicate that the time has not been set. --HappyDog 09:29, 5 October 2007 (UTC)


 * Actually when the clock is not set it flashes 00:00 to alert you... but that is a good point because when you use the timer, which is on the same display, it goes to 0:00, so using 24:00 for the normal clock at midnight reduces ambiguity. It's a German cooker so there almost certainly is a rational reason for it ;) -- Borb (talk) 17:57, 2 April 2008 (UTC)

24 time does not have ":"
Sources      DXRAW 23:29, 17 January 2007 (UTC)


 * The colon-free 24-h notation is indeed characteristic of U.S. military usage (see your references), UK railway usage and some computer formats. However, im most other uses (e.g., email headers, television in Europe and elsewhere, digital wrist watches, even Wikipedia) in everyday civilian live in many countries, the colon (alternatively in some countries also a dot on the line) is used. I find it increases readability. Both the colon and colon-free notation are covered by ISO 8601. I will therefore revert your removal of the colons from the conversion table, as it does not reflect the most common (or IMHO even most readable) variant of the notation. Markus Kuhn 09:51, 18 January 2007 (UTC)

Pronunciation
How do you pronounce the times of the 24-hour clock? There is a pronunciation section at 12-hour clock; why not one here? I am confused and would like that information on the 24-hour notation.142.176.114.191 03:06, 14 February 2007 (UTC)


 * Are you suggesting that we rename the existing section "The 24-hour clock in spoken English" into "Pronounciation" or are you saying that anything important should be added to that section? Markus Kuhn 09:31, 15 February 2007 (UTC)

24:00
I wish there was a 24:00, as I absolutely could use a 25 hour day. Our day begins at zero hundred hours with midnight and ends at 23:59. 1)00:00-00:59 2)01:00-01:59  3)02:00-02:59  4)03:00-03:59  5)04:00-04:59    6)05:00-05:59  7)06:00-06:59  8)07:00-07:59  9)08:00-08:59 10)09:00-09:59  11)10:00-10:59 12)11:00-11:59 13)12:00-12:59 14)13:00-13:59 15)14:00-14:59  16)15:00-15:59 17)16:00-16:59 18)17:00-17:59 19)18:00-18:59 20)19:00-19:59 21)20:00-20:59 22)21:00-21:59 23)22:00-22:59 24)23:00-23:59

This system would leave no room for alarm errors. Betwixt Words 22:29, 9 June 2007 (UTC)


 * If you treat the day as the semi-closed interval [00:00,24:00[ that includes midnight at the start of the day and excludes midnight at the end of the day, then you are right, and this is indeed the convention used on most digital clocks and computer displays. Nevertheless, the point-in-time notation "24:00" is useful for explicitly referring to midnight at the end of a day (and even if just for the purpose to clarify unambiguously that 00:00 refers to the start of a date, not its end, or for writing down the above excluded interval endpoint), and is for that purpose explicitly mentioned in ISO 8601, the international standard for the 24-hour clock. But then, the article explains all that already quite clearly, doesn't it? Markus Kuhn 22:58, 9 June 2007 (UTC)

Most clocks are set as to display the minute that is beginning using a half-open interval [00:00,00:01) (left endpoint convention). However, do the clocks that run from 00:01 - 24:00 use a right endpoint convention (00:01,00:02]? Zginder 12:23, 27 September 2007 (UTC)

Merging military time

 * The military time article seems to cover exactly the same material and should be merged into this article IMHO. Markus Kuhn 14:47, 6 November 2007 (UTC)
 * I disagree with this position, this is exactly the reason why I added the seperate topic of military time. Previously this topic did redirect to 24 hour clock. However I see military time as a subform of 24 hour clock, which also adds the constraint that no seperating ':' is used and leading zeroes are added to ensure a military time always consists of 4 characters. As explained in the text. I do agree with Markus Kuhn that the document doesn't have the right wiki layout and could be brought up to speed. Perhaps more information could be taken from the referenced page. Bart van der Wal 12:42, 15 November 2007 (UTC). — Preceding unsigned comment added by 193.172.35.3 (talk) 11:44, 15 November 2007
 * If the only differences are minor stylistic variants in the way times are written down, then military time should be merged into this article. We can always add one or two sentences describing the distinction. -- Indefatigable (talk) 19:27, 16 November 2007 (UTC)
 * BvdW's reasoning for creating an apparently drastically redundant article is silly. I'll do a cross-articles diff, to flesh out MK's observation, & provide the lk before merging the two articles, but there's no reason for further delay. --Jerzy•t 21:00, 2 April 2008 (UTC)
 * I agree, it should be merged. Wjw0111 (talk) 22:47, 17 March 2008 (UTC)
 * I vote for merging it. Essentially "military time" is no more than a regional (North American) term for the 24-hour clock. None of the stuff about leading zeros or missing colons between the hour and minute is specifically military. Both are common in civil aviation, weather-reporting (take a look at the time-stamps on satellite photos for example) and other non-military technical fields. The ISO 8601 standard specifies that the hour should be "zero-padded". —Preceding unsigned comment added by RB1956 (talk • contribs) 05:37, 6 June 2008 (UTC)

Judging there was consensus over two years of waiting (with 5 signed in agreement, 1 unsigned in disagreement), I performed this merge. Hult041956 (talk) 01:45, 5 November 2009 (UTC)

24 * 60 why not 12 * 120 or 10 * 100
Who knows why we got a) 2 dozens of hours in a day and b) half a dozen times 10 minutes an hour?

a) Makes sence, since as is written [Comparison of the 12-hour and 24-hour clocks|here] there are some advantages, as the days lasts normally from 7:00 AM to 7:00 PM, but why are there just exactly 12 hours? - Ok, it's a dozen. but shouldn't we change that into some metrical unit? b) The same as in a) at the end. --83.219.124.37 (talk) 16:02, 17 December 2007 (UTC)
 * As to why, Babylonian mathematics should cover it adquately. As to what we should do abt it, WP does it's its part to change the world by reporting how it is in a free-information mode, not by working out plans for the change. --Jerzy•t 21:05, 2 & 03:57, 3 April 2008 (UTC)
 * You might also want to have look at decimal time. &minus;Woodstone (talk) 05:11, 3 April 2008 (UTC)

Shouldn't this page be at Twenty-four-hour clock?
And 12-hour clock at Twelve-hour clock, since Naming conventions (numbers and dates) states that:


 * "As for events that don't recur on (semi-)regular intervals, article titles containing a reference to a time period (not a date) are not bound by strict rules, apart from using the most common name. However, generally, in these cases numbers are written in text, and abbreviations are avoided. Some examples:
 * Four year plan
 * Hundred Years' War"

--Paul_012 (talk) 18:21, 17 May 2008 (UTC)


 * But, they "recur on regular intervals," every 12 or 24 hours.Zginder 2008-05-17T21:01Z (UTC)


 * The part about recurrence was referring to events mentioned in earlier sections in the convention page, e.g. SummerSlam (1999) or 2000 Summer Olympics. The clock system is not an event, but "24-hour" serves as an indication of duration, so this article should follow the above-cited guideline. --Paul_012 (talk) 14:19, 20 May 2008 (UTC)

Almighty Google suggests that the current (numeric) article name is vastly more common than the proposed non-numeric version, so I suggest to follow the quoted naming convention and stay with the most common name: 24-hour or 12-hour clock. Markus Kuhn (talk) 17:24, 22 May 2008 (UTC)

Ovens with 24:00 instead of 0:00
I got a bit curious about why some ovens display 24:00 instead of 0:00 and which ones do it. So I emailed the BSH (Bosch-Siemens, who make Neff ovens too). Surprisingly I got a quick reply. Kudos to them for taking an interest! Here is what they had to say:


 * I had never noticed this and was not aware convention dictates that the clock is expected to show 00:00 as opposed to 24:00.


 * I believe that ISO 8601 is the relevant standard, but understand that this does not define whether 00:00 or 24:00 should be used and appears to actually recognise both as valid times. 00:00 however, appears to tbe the prefered display for midnight, and although some argue 24:00 is not a vlid time, there seems no reason (other than "convention" why we cannot use 24:00.


 * Frankly, I suspect that this is nothing more sinister than the fact that this is simply the way the clock was configured originally. I would be surprised if there was any attempt to differentiate the clock and the timer functions (why would there, as for every other minute of the 24 hour day, the settings are identical).  Put simply, I think this is just the way it is.


 * As for Siemens and Bosch, [Borb] will no doubt be pleased to learn we stick with his prefered 00:00 display at midnight.

Well there we go... to those that were also curious. It seems that only Neff ovens do it and there isn't really a reason for it, it's just another way to display midnight. -- Borb (talk) 20:31, 17 September 2008 (UTC)


 * I think that 24:00 clocks should be set one minute ahead of 00:00 clocks as the former display the time just before the change and the later right after the change, IMOHO. Zginder 2008-09-18T03:21Z (UTC)

Military avoiding 00:00 and 24:00
The reference for the military avoiding 00:00 and 24:00 contains the phrase "eg 0000.5 for ½ a minute past 2400". This shows clearly that they have not understood. If there is any meaning attached to "½ a minute past 2400" on a particular date, it would most certainly not be the same as 0000.5 at that same date. &minus;Woodstone (talk) 16:39, 1 February 2009 (UTC)

New "disadvantage"
I have taken the liberty to be bold, and I have added this disadvantage: In terms of pronunciation, a specific 24-hour notation time such as "19:59", said as "nineteen fifty-nine", may sound too similar to and be mistaken as the calendar year 1959. Though this issue has been nonexistant since 1960, it may resurface after 2010, when the pronunciation "twenty ten" (20:10) may become more prevalent than "two thousand ten" (2000–10). If anyone finds it inaccurate or misplaced, please discuss here. Thank you. — 142.176.125.209 00:05, 16 February 2007 (UTC)


 * In English, different prepositions used for years and times-of-day can help to resolve the ambiguity: "It was a snowy Sunday evening in 1959 when I heard at 19:48 a loud bang on the door ...". In some other languages, there is a well-established short word spoken in place of the colon, such as "19 Uhr 59" in German and "19 heure 59" in French, which denotes as unambiguously a time-of-day as am/pm do in English. I guess the equivalent "19 o'clock 59" won't succeed in English because "o'clock" is a rather awkward two-sylable construct (as are "a.m." and "p.m."!). Perhaps "19 hours 59" (or even "19 and 59") would become acceptable if someone started using it prominently?
 * So I would perhaps reduce the claim slightly to "In English pronounciation, there is no well-established convention to disambiguate a 24-hour time from other 4-digit numbers, such as years." Markus Kuhn 13:41, 16 February 2007 (UTC)


 * Well, that's not quite a flagrant disadvantage. At a workplace in the US for example, we often say something in the lines of "Hey, I'm coming in at 8 tomorrow". Does that mean 8 am or pm? Most of the time the other person is left guessing. However, if I say I was born at 19:59("nineteen fifty-nine")" it is pretty distinct from "born in 1959" due to the use of prepositions as mentioned above. The context also plays a huge role. If I am asked what time I was born, it is pretty obvious that my answer can't be mistaken for a calender year. It would be interesting to read about more solid disadvantages. —The preceding unsigned comment was added by 72.134.37.128 (talk) 05:34, 10 May 2007 (UTC).


 * What, seriously? Nonsense. You just told a co-worker when you'd be showing up at work. If they're confused, they aren't qualified to be working. Or should I just say "citation needed"? J.M. Archer (talk) 16:56, 12 March 2010 (UTC)


 * Oh a co-worker could legitimately be surprised. A lot of jobs involve overnight working and staff working a mixture of morning, afternoon, evening and overnight shifts so everyone shares the pain & gain. Timrollpickering (talk) 13:39, 25 June 2010 (UTC)


 * Markus Kuhn's objection to this disadvantage stands, in my opinion: the ambiguity between times and years (19:59 and 1959) is not present in many languages, because years are not necessarily pronounced as pairs of numbers, century and then year. In several languages spoken in Europe (both Indo-European and non, for example Finnish) years are almost always spoken as integers, in other words "one thousand nine hundred fifty nine". In some of those languages where the "century + year" method is used (like Swedish) there is still no confusion between times, since the word "hundred" is added, translating to "nineteen hundred fifty nine". This disadvantage of the 24 hour clock is a disadvantage only in languages that insist on using century splitting when talking about years after 1000 CE (excluding for some reason the years 2000-2009?). Arcades (talk) 23:42, 25 May 2009 (UTC)

AM and PM
Under the History section, it states "the familiar "a.m." and "p.m." suffixes". Is a.m. and p.m. familiar? And to whom? —Preceding unsigned comment added by 83.163.43.116 (talk) 00:52, 9 April 2010 (UTC)

"Military time" used to refer to 24 hour with decimal minutes
A friend of mine recently started working for the United States Postal Service, and she informed me that she was very confused by the military time used there, and that people in her workplace would sometimes just wait for the hour to come around before signing/clocking out so they wouldn't have to do the math.

Obviously this confused me, as I was under the impression (as is this article) that all it took to read military time is subtraction by 12 (or more pretentiously: perform rudimentary modular arithmetic =P).

When I looked at her schedule, however, I found that by "military time" the folks at the post office were referring to an odd system with 24 hours to a day and 100 minutes to an hour. E.g. on her work schedule "23:50" would correspond to 11:30pm in the twelve-hour system.

Is this usage common in the United States? In certain industries? Anywhere? MarcelB612 (talk) 02:30, 4 June 2010 (UTC)


 * Indeed in systems using "punching in" (and out) for registration of working hours, a division of the hour in 10 (or 100) units has been common. It makes calculating the hours worked much easier, since the subtractions (out-in), additions (totalling over days) and multiplications (hours times hourly wage) can be just done decimally, by hand or on any simple desk calculator. There is no need to convert to minutes. With the advent of electronic registration, these calculations can be done in the computer and are mostly back to hours and minutes. And by the way, "waiting for the hour" was done to profit from 0.1 hour (6 minutes) extra registered time. &minus;Woodstone (talk) 09:46, 4 June 2010 (UTC)

Practical problems
How come is a practical problem that analog clocks don't display 24 hours? Most parts of the world have 12-hour clocks and use the 24 hour system... we are just so used to adding 12 that everyone understands 20h means 8pm without thinking about it. How can that be labeled as a 'practical problem'?? Same goes for the fact that striking clocks don't ring 23 times the bell at 23:00. Is it so important that it can be called a 'problem'? Loqu (talk) 19:48, 21 July 2010 (UTC)

Broken link
U.S. Government Printing Office, Style Manual is a broken link. Avihu (talk) 12:28, 23 July 2010 (UTC)


 * "Communication instructions – General, Allied Communications Publication ACP 121(H), Combined Communications-Electronics Board, April 2007" is also broken. Avihu (talk) 17:12, 23 July 2010 (UTC)


 * Fixed the first, tagged the second . Adrian J. Hunter(talk•contribs) 03:53, 24 July 2010 (UTC)

Self contradiction ?
The article states: "Legal contracts often run from the start date at 00:00 till the end date at 24:00. It should be stressed, however, that "24:00" is a notation for the purposes of clarity and does not represent a distinct clock time." -- If it does not represent a distinct time, how does it add clarity ? I must be misunderstanding something...76.113.105.186 (talk) 09:29, 11 August 2010 (UTC)


 * It represents a well defined time: the very end of the specified day. It is not distinct from 00:00 the following day. But in a contract it is usual to specify the end as the last day it is still valid, not the first day it is not valid anymore. So from 1 Jan 00:00 till 30 June 24:00 would run precisely 6 months. Very clear and not confusing. Much better than stating from 1 Jan 12 a.m. to 30 Jun 11:59 p.m. (not totally clear about the first half day and the last minute). &minus;Woodstone (talk) 12:22, 11 August 2010 (UTC)


 * 23:59:59 represents an accurate time, but my understanding is that there is no 24:00:00. The time goes from 23:59:59 to 00:00:00 to 00:00:01.  Since there is no 30 June 24:00, the six month period would never arrive.  A more accurate phrase may be from 1 Jan 00:00:00 through 30 June 25:59:59 or until 1 July 00:00:00. Tesseract501 (talk) 16:04, 6 December 2010 (UTC)
 * Unless we are referencing military time. My understanding is that midnight is called 24:00:00, with one second after midnight being 00:00:01. Tesseract501 (talk) 16:08, 6 December 2010 (UTC)


 * Yes there is a June 30 24:00 and it is exactly equal to July 1 00:00. Midnight, being the boundary between two days, can be seen from two sides. It is one instant with two notations. The ISO standard is fully clear on this. A physical clock would not show 24:00 for an infinitesimal instant, but jump immediately to 00:00 (although some appear to actually show 24:00 for the first minute). &minus;Woodstone (talk) 18:30, 6 December 2010 (UTC)

Comparison List in Military Time Confusing
Military Time section currently ends with a list of differences from civilian time. This is confusing, because it describes what military time "isn't" when I'm trying to read what "it is". I think a separate section would be helpful, titled, "Differences Between Military and Civilian Time". A table would be excellent for that purpose. Or switch list to a table with a title on, that would be better, but separate section would be best.Catrachos (talk) 15:27, 10 February 2011 (UTC)

More Detail, Clarity Needed for Military Time
It's pretty easy to grasp the top of the hour idea for military times, add 12 to PM times; more difficult are between hour times and pronounciations for between hour military times. The following would be useful additions to Military Time: Explicitly describe difference between top of the hour ("zero nine hundred hours") versus between hours ("zero nine thirty hours" and how they are pronounced, my understanding is "drop the 'hundred'"). Mention differences between services; I'm told Marines always say hours ("zero nine thirty hours) while you don't hear hours, in informal speech at least, for other services ("zero nine thirty"). Discuss "oh nine thirty hours" versus "zero nine thirty hours". Is "oh" frowned on, or is it accepted usage and when is it not accepted? It seems to me that "oh" is commonly used in speech. However, radio operators particularly always use zero (zero one hundred hours for 0100, or zero zero zero five hours for 0005) to avoid any chance of ambiguity. Catrachos (talk) 15:33, 10 February 2011 (UTC)

I think this section is overly involved with "military times" as it is. Maybe it should be split into two parts, because the rest of the world uses the 24-hour clock, and we don't call it "military". Just the US and a few other related countries use 12-hour clocks. The 24 hour clock is more clear and states exactly the time you are referring to, without adding letters to numbers. 24-clocks are extremely clear, they run from 0 to 24 in an orderly fashion. 12-hour clocks are the weird ones, as they start at 12, then go to 1 up to 11 and then they switch from am to pm.

The only thing you actually need to do when converting from military time to time in general is that the day starts at 0 and ends at 24, in one-hour increments. So 18:00 is 18 hours since the day started. That is, 6 hours from noon. That is, 6 pm. I don't think it's rocket science.

This is an article about _24 hour clocks_, not the US military (or any other military, except from the ones in 95% of the world's countries, that don't need an overly complex time system because they learned the proper one in school). —Preceding unsigned comment added by 129.12.130.70 (talk) 17:00, 17 March 2011 (UTC)


 * The article is actually wrong as it now stands. It reads


 * "Hours" is usually not appended in civilian use (1500 hours may be pronounced "fifteen hundred hours", which is unusual in a non-military setting), nor in Royal Navy usage.


 * In the military (certainly in the U.S. Navy where I did my time), The word "hours" is regarded as unprofessional nonsense best left to motion pictures and civilian law enforcement. You don't use it.  It's not that civilians don't use it whilst service personnel do, it's that service personnel ought know not to use it but civilians (who watch too many movies) think the service does.  Accordingly, I am striking that bullet point. RobertSegal (talk) 18:02, 29 March 2011 (UTC)


 * I also just deleted the bullet point stating in error the military does not use the designation "2400". Absolutely we did.  Midnight is written 0000 and spoken "twenty-four-hundred" or simply "midnight". The midnight-to-four AM shift is usually referred to colloquially in the Navy as the "balls-to-four" watch because midnight written out looks like OOOO.  (But if someone asks what time it is, you never look at your watch and answer, "Balls" and certainly not "Oh-oh-hundred".  You just say, "Twenty-four-hundred, Shipmate".) RobertSegal (talk) 18:41, 29 March 2011 (UTC)


 * I just realised I left out an example of military use of "2400" in written text. We would write that Joe would be on watch from 1600 to 2400 and then James would take his place from 0000 to 0800.  So, anyway, the article was wrong and the statement called for deletion. RobertSegal (talk) 18:45, 29 March 2011 (UTC)

Can somebody address the case 1000? Should it be "ten-hundred," "one-thousand," or other? 71.92.71.203 (talk) 08:06, 17 January 2012 (UTC)

Let me try and enlighten you
It appears from this article as well as the 24 hour clock article, which I will cc this comment to, that most if not all editors on this subject have missed the concept of a clock completely. Though, it is understandable to me because I myself did not make this realization until recently.

It is quite amazing to see that the creators of this ancient time measurement system seemed to understand this deep fundamental concept and was never questioned. While now all these smart anonymous editors don't even sense the concept rushing past them due to their weak reasoning.

Now that I am done being rude, caused by the confident, yet wrong, content of this article, let me prove my worth; though I will warn you I am not good at transcribing my thoughts to natural language; I will try my best; please bare with me.

The first thing to understand is that there is no such thing as Time = zero. When Time = zero it means you are dead. It does not exist because time only exists to you because you are alive to perceive it. In other words, the moment in time is a function of your unitary perception of all the preceding time before that moment such that your unit of perception is to the power of e.

Heh, let me try and explain that again. T = f(x):=e^x So when you born, that absolute infinitesimally tiny moment when you perceive life. That is one unit of time, as soon as you continue to live for another one of those units of time, that is now the second unit of time. http://en.wikipedia.org/wiki/E_(mathematical_constant) see this article for help understanding what I mean. Time would be the Y in the graph. As soon as you first perceive life, when x=0 time is 1. This is why there is no year zero. This is why there is not time 0:00 on a 12 hour clock. This is why I think a 24 hour clock is strange. Having time go from 23:59 to 24:00 then to 0:00 then to 0:01 makes no sense unless you share 1 second between 24:00 and 0:00.

There is a comment somewhere that says it is ambiguous as to whether midnight is the start or end of the day, yeah, no shit. You tell me what it is! A day is not an isolated universe of time, it is part of a continuous fabric of time that has not start or end. The end of the day is the start of the next day, there is never a moment when Time = zero as soon as the big bang happened time was 1 and has been increasing ever since. Time was 1 if you think that there must be a fraction of a moment before that first 1 then whatever fraction you are imagining would be the unit of time so that would be 1. As soon as there is existence time has already been created and it's increasing.

The present is an infinitely small moment of time that is imperceivable, as soon as you notice it, it has already passed. You exist physically in the present but your mind exists by watching time fly towards you and then past you into the past as it gets locked into the memory of the universe and irrevocably stamps it's impact on all future events.

This can be intuitively seen and understood by every person. We all know that each year of our childhood felt very long. And as you get older every year seems to go by so much faster! This concept shows up in pop culture with sayings from kids like, "Are we there yet?" and old people such as, "It was just like yesterday."

The reason this is is because say you live for 1 year. Then you live 1 more year. You just doubled your life! As far as you are concerned you just lived for forever! Twice! Which becomes the new forever. And as you become 50 once you live one more year that is no longer as large an amount of time. It is only 1/50th what it used to be.

So the reason 12:00 the one that happens during the daylight where you are. Is called 12:00 pm is because as soon as 11:59 ticks one unit to 12:00 there is units less than a second we cannot comprehend that have already begun counting up. Once they reach 1 second it becomes 12:01 pm which is clearly the afternoon. So since some people like to clarify 12:00 when it is sunny with 12:01pm and not just 12:00pm, just think it is really 12:00:00:00:00:00:00:01 the moment it flips from 11:59 am.

That is why there is no 0:00. And I would love to hear from some electronics engineer explain how a 24 hour clock can display both 24:00 and 0:00. I did not realize time did not exist for 1 second everyday. I just am not sure if that second is at the 24th hour or the zeroth hour. Heh, zeroth hour, funny people and their made up symbolic lies.

I like how people think that when zero was realized to be a number they think that means it can exist. I'm sorry, zero does not exist. That is what zero is, none existence. It is what is inside that little circle we use to show it's concept. If you have 4 apples, and you give away 4 apples you don't walk around with a special magical apple known as your zeroth apple. You walk around empty handed saying, "I have zero apples!"

That is why the month does not start on day zero and then move to day 1. The month starts on 12:00am actually. Which is also the end of last month in our macro world. Maybe some electrons get to tunnel into that zeroth second and freeze in time for who knows how long then popup somewhere else randomly. But that's the great thing about the universe! It's made up of real existence held together by irrational imaginary chaos.

Maybe that's where my mind lives, I hope you can join me there too and not just try to argue unsuccessfully against me. Because I would love to hear a justification on how, "The rollover from 12 to 1 happens an hour later than the change between a.m. and p.m." this sentence is even remotely disadvantageous.

I forgot to sign, that would have been a shame, eh? Rukaribe (talk) 12:11, 29 October 2010 (UTC)


 * I'm afraid you have completely failed to understand the real numbers. Quietbritishjim (talk) 02:29, 18 November 2010 (UTC)


 * Having read a few more lines of your comment (why did I subject myself to that!?) I now realise it's an elaborate troll (maybe that's a bit harsh; it seems like you're parodying something, but I don't know the background). Still, in the spirit of good faith, I'll leave my original reply up there. Quietbritishjim (talk) 02:36, 18 November 2010 (UTC)


 * So how many lines have you read in total after your second comment then? It is not the most rigorous piece ever written and is quite condescending but I do know of the real numbers. They are just damn confusing. Thanks for at least thinking it was elaborate but unfortunately I am no troll, I am quite serious though my meaning may be lost in my poor natural language and disjointed thinking.

After reading my comment again: I think it is important to keep in mind the context of where my mind was when I wrote this. It was in relation to the enumeration and display of time as defined sets of positive integers. You say I do not understand the real numbers, you are correct I find them quite mind blowing. But I think that is beside the point, the point is you have constructs involved in this situation that cannot be fully explained by mathematics currently. Trying to understand time means you need to understand life I feel.

I wish you didn't just think I was some troll because I think there is more here than you may admit. Time is a ring, with any moment of time you define the end of it is the beginning of the next one. That is what I said when I said every months starts on day 1. Every week starts on the 1st of 7 days, not the 0th of 6, like I said if time is zero then time has stopped and you must be dead. The real numbers may explain this in a normal system but the boundary of time is undefined. In order to know what time is like when it is zero, algebraically you would need to divide by zero to learn that at some point and we all know that cannot be done.

Clocks cannot show real numbers, that is my point. Instead we created a looping system with different magnitudes of looping based on real physical events at our scale. If anything it would have been best if they just slowed clocks down and made each hour a half hour and had 12 hour days with one revolution of the hands about the face. It may seem like an odd idea but that is mostly because traditional time is so ingrained in us now it would seem strange. But I think it would be a good system if we knew of nothing else and could start fresh. I also think we should have a universally defined unique symbol for each month and day of the week that is as powerful as numbers and letters in terms of semantics. That would make dates in computers so much easier assuming a proper encoding system was created in this hypothetical world in my head.

So, if you ever do reply again. Do you think we should start counting time at zero? Can you explain why a 24 hour clock can have a time 24:00 and 0:00 without gaining and extra second? Will you actually read my complete comment and try and unearth what I am trying to say? Because I'm pretty sure if you overlook whatever errors I make in the details my overall philosophy might seem pretty compelling. Cheers! Rukaribe (talk) 19:26, 25 November 2010 (UTC)


 * Whatever that may be about, it's not about improving this article. — Arthur Rubin  (talk) 21:03, 25 November 2010 (UTC)


 * I have read your comments. I will reply properly, but it's a bit late at night for me to do it right now.  For now I will say three things: (1) I stand by my original (first) comment (2) I agree with Arthur Rubin (3) I will ask about an analogy to try and help figure out your thinking:
 * Most people would consider time (even the 24 hour clock that measures it) as real numbers. This is just like e.g. distance.  So imagaine I'm 10km away from you, and as you walk towards me there's 9km between us, then 8km, then 7km ... then 1km, then finally we're at the same point so we're 0km apart (ok so you'd leave some personal space, but in principle we could get pretty close).  Would you say that there wasn't really 10km between us at the start because that doesn't include zero?  That there was really 11km between us (but then there would have been 12km by the same reasoning, etc)?  Or do you consider this example doesn't work because we couldn't really be 0km apart, and that's your whole point? Quietbritishjim (talk) 00:47, 26 November 2010 (UTC)


 * First, I feel it can help improve the article by explaining an overall reasoning for why the 12 hour clock exists the way it does. It just seems there are a lot more people on the 24 hour clocks side on the internet.


 * As far as your example the issue there is you have two different objects converging. With time it is looping back to itself which is what makes time so odd. Also with the dimension of space a length always has a definite beginning and end. It may be relative to where you define the point of origin but there is always a definite magnitude that can be represented with a real number like you said. Like with a finite value of an infinite series.


 * The special issue with time is that time in your perception on exists once you exist. So as soon as you are alive, whatever that is, then time has already started. I think of it kind of like an annuity. You have annuities due and annuity immediate an annuity due you make a payment at the beginning of the month while an annuity immediate you make at the end of the month (if you are the investor). When I learned about these in school they called the annuity immediate an ordinary annuity for simplicity because the word immediate makes it sound like it would supersede an annuity due. The reason they use this terminology is because an annuity due as soon as it is legally agreed to, is already due. The infinitesimally small moment after you create it, it was due and you are already technically late but humans are nice and give minor grace periods. While the annuity immediate is due immediately at an up coming time, which is usually a month.


 * This is part of the same concept, how there is no moment to experience time zero. Because it's zero, there is no time then so you can't enjoy that moment of zero time. It doesn't exist by definition and you can never experience it. This is why interest is compounded by the exponential function also because it is purely a function of time while humans are alive and creation economic growth by creating capital from our attempts to reduce entropy.


 * So back to your point, you did predict my reply. Since there are two objects here they can never be in the exact same location and they will never be at 0km. The Pauli exclusion principle demonstrates why this is nicely.


 * Also do you mean to say originally that I don't understand rational numbers? You seem to be using those to explain your example and not real numbers, to me it seems the real numbers actual help explain what I am saying more so. Such as e and pi combining to explain the looping aspect of time as it continues at some rate. My view also fits nicely with relativity as far as I can tell without getting into it too far.


 * Anyways, this is probably not helping the article so I will cite some simple corrections. The main one is the claim that there is confusion whether 12 noon is 12:00am or pm. I see no confusion here, it is pretty clear since as soon as 11:59 ticks over to 12:00 it has switched to the afternoon, this is when the sun is directly overhead so it makes sense. You can think of 12:00 counting to 12:59 then 1:00 as going from your time 0 to time 1 on a scale of hours with fractional minutes. The key is that it is also the last hour of the prior half day break. The only reason this happens is because you never truly are at time 12:00 because as soon as you reach it you pass it and are a millisecond into the afternoon.


 * Days work differently because a day does not get a fractional time period attached to it. It exists as it's own unit which starts at one and goes until the end of that month. You can think of a day like an annuity due where an hour is an annuity immediate because we can just keep making more precise rational numbers as units of time and then put a colon between them and the prior units. Based on that convention you can break time down as much as you want, but you will never get to time = zero.


 * From what I read the only reason 24 hour clocks show 0:00 and 24:00 is for convention to reduce the inherent ambiguity. The issue is how the circuit is coded. Do they just make 0:00 and 24:00 last half as long as normal? Or do they just alternate each day with which notation they display at that moment. I wrote this originally for the 12-hour article mostly because it does contain many odd statements. I like this one particularly, "The rollover from 12 to 1 happens an hour later than the change between a.m. and p.m." it is listed under the header of "Criticism and practical problems". I am not even sure how to address this statement really. So the writer thinks it makes more sense for 12:00 to count all the way up to 12:59 then switch to pm when it ticks over to 1:00? How do you even respond to that? Since 12:00 is the end of one day or half day and the microsecond later the start of the next why would you let 12 count up? It's simple, If time > 12 then it's crossed over into either the second segment. It doesn't matter if it's 1 minute past 12 or 1 micro second. It's still crossed the 12:00 mark and is not approaching 1:00. Anyways, I feel like I'm beating a dead horse at this point now.


 * I hope you are starting to see my point because I think it may be more fundamental and provider deeper explanation than you gave it initial credit. It's just a shame I suck at transcribing my thoughts I guess. Rukaribe (talk) 02:37, 26 November 2010 (UTC)
 * To answer an implied question: A 24-hour clock almost always shows 00:00.  24:00 is a convention to show midnight of the next day, in cases where, say the time interval, 23:00–00:00 looks odd.
 * And the question of, on a 12-hour clock, whether noon is 12 am or 12 pm, only applies to noon itself. 12:01 pm is in the afternoon, but 12 pm may be ambiguous, and possibly 12:00 pm.  — Arthur Rubin  (talk) 16:28, 26 November 2010 (UTC)


 * There is no implicit questions in my comment if that is what you mean. I'm not sure what makes you think I am implying a question that you must answer for me so please don't read my comments in a manner of presumed ignorance on my part that you must correct. Rather, read it in a fair an open manner. You can presume I am a horrible writer based on the evidence if you wish. But please do not presume ignorance.
 * You can see I said, "...and 24:00 is for convention to reduce the inherent ambiguity. The issue is how the circuit is coded. Do they just make 0:00 and 24:00 last half as long as normal?". You have not answered anything I can even extrude into an implied question. I started that it appears to be a convention which you confirmed, thanks. But the question I overtly asked on the technical merits of the implementation of this convention which are quite important for the defense of this article. A clock cannot simply add in a whole extra minute of falsely displayed information and claim to be even remotely accurate for any situation. Like I said they would need to make 0:00 and 24:00 both half as long or never show 0:00 and go straight to 0:01 after 24:00. That would be a useful answer.
 * The fact that the 24 hour clock needs to be literally wrong by convention to improve it's interpretation is not a benefit in my eyes. It says that the clock needs to be incorrect to be easier to use, yet this article is written in a condescending pompous manner in which individuals who use the 24-hour clock view themselves as smarter and superior to users of the 12-hour clock. When in reality I just demonstrated that the 24-hour clock is only superior for people with a lack of understanding of how time works. I'm trying to be nice after the condescending comments and whole article in general.
 * The last thing you said I do not quite get what you are trying to say. I think because you put noon in quotes and I don't know what you are trying to get across with that unspoken emphasis. But I think you missed the point of my explanation. Think of it like this, there is no such thing as 12. As soon as you hit 12 a tiny amount of time passes and you are not one second into the first minute of the 12th hour of the day. That means you are over 50% into the length of the day and therefor in the afternoon. You can confuse this am pm thing with every hour of the day since the 12 hour clock splits the way in half and repeats the notation with an operation identifier to clarify which half. This is a good argument for the 24 hour clock and better than most of the others listed.
 * Like I explained with my annuity due example, the proper manner to handle this situation in places like contracts would be to clarify whether the stipulation is due at the start or end of the time interval listed. This would clarify the incomprehensible tiny moment of time when the stipulation is due and at which end of that immeasurable moment it is due. This isn't quite necessary since seconds are usually accurate enough.
 * To the last thing you said, you are mixing up the idea of ambiguity and incorrectness. It is not ambiguous whether the notion of noon is 12 am or pm if you understand the concepts I explained above. 12:00 is the start of the half day as well as the end of the previous half day. When you go from 11:59 to 12:00 it switches over and since the morning is understood to be the am then when it switches to 12 it is the pm the moment that happens. You are not truly at 12:00 you are at 12:00:00:00:00:01 or however accurate you want to get. This should be obvious and clear, everyone knows 12:01pm is the after noon. Everyone should similarly know 12:00pm is the afternoon for the same reason. I'm sorry if you think this is ambiguous, I think it's just lack of understanding. If you wish the 24-hour clock is more user friendly for un-knowledgeable people by all means do that. But don't act like you are superior because you use the 24-hour clock because that does not appear to be the case.
 * Sorry if you find that rude but I am simply following the golden rule and reacting to your comments. —Preceding unsigned comment added by Rukaribe (talk • contribs) 02:55, 7 December 2010 (UTC)
 * Nice rant. It has nothing to do with improving the article, but it is a nice rant.  There's no "half-minute" in 24-hour clocks showing 00:00 or 24:00.  Most show the former, but some apparently show the latter for one minute.  Now, there does seem to be an anomaly in 12-hour clocks if you consider the change from 12:59 to 1:00 to be significant, as it is different from the change between am and pm.  — Arthur Rubin  (talk) 16:54, 7 December 2010 (UTC)
 * Thanks! As per improving this article I think it is best to consider all written here to apply to this article as well as the 12-hour clock article which I linked to. Since that article is written to basically make 12 hour clock users appear inferior it's not from a neutral point of view in my mind and all the reasons I outlined clarify why that is I feel.
 * The am pm change you just mention does not matter, you can switch from am to pm and vice versa whenever you choose as long as the two times are equidistant apart for the total length of the day. The reason it happens are 12 and not 1 is because it's to show the hour is not the smallest unit of time we use. In reality it should happen at some tiny fraction of a second after 12 and the exact precise time of 12 should be neither am or pm but we can never exist then. That makes no sense though and is caused by the 12 hour clock, if that creates the ambiguity in your mind then I see your point.
 * My point is that if you think of it such that as soon as it becomes 12:00, already 1 millisecond has passed, so it is now passed 12 and into the afternoon. I tried to explain this concept with the annuity due and annuity immediate example.
 * Think of the time like a loop and the end of the day is the start of another. That is why you cannot say 12:00 is the start or end of the day definitively unless you also specify the day. Any ambiguity is more so caused by the lack of a date than whether it is morning or afternoon. If anything the mental math needed to do is more ambiguous than that to most people. Well from where I am from anyways where 12-hour clocks are most common.
 * Really though, who likes to subtract 12 from 17 and 19? Yuckie.
 * Also, I have no idea when they first started the first official clock whether they started it at 12 or 1 but I think that would be interesting to learn. :)
 * Rukaribe (talk) 22:34, 3 January 2011 (UTC)

Quote: "I am not good at transcribing my thoughts to natural language" (by OP). Reply: You're right. 68.35.66.170 (talk) 03:31, 22 April 2012 (UTC)

How can I confirm this?
"Digital clocks and watches using the 24-hour system show 00:00 at midnight. As a rare exception, the digital clocks on some microwave ovens from Bosch Siemens, a European manufacturer, show 24:00 for midnight.[citation needed]"

I have a such microwave oven. If I take a photo and upload it, will that do? --83.226.119.93 (talk) 12:09, 19 June 2011 (UTC)


 * I think it's much more common than it is rare, and I checked my oven and it does it too, and made a generalization accordingly. I found a picture already in wikimedia and inserted it, so another one isn't necessary (but why not upload it to Wikimedia anyway?). The reason they do it is simple: when mains power is re-applied, the display says 0:00 (sometimes flashing) because that's the default 'unset' time. So showing 24:00 is logical - shows that the power is still on and that the clock is ticking. After a minute it says 0:01. Of course, British cooker but Japanese electronics - so no AMPM anywhere.  Cormullion (talk) 09:56, 8 July 2011 (UTC)

"Railway time" and "continental time"?
The article introduction claims that the 24-hour clock is called railway time or continental time "in some parts of the world". There are no references supporting that statement, but there are links to the articles about railway time and continental time. So, naturally, I click on those to find out where in the world this is common.

However, the article about railway time is mainly about how the introduction of railways around the world in the second half of the 19th century necessitated the move to standardised time in each country (instead of every village keeping it's own time based on a sun dial). There is a sentence about Moscow Time being used today on Russian railways throughout the nine timezone country, but that hardly means that the Russians call 24-hour notation "railway time". I also seriously doubt that timetables for local trains in the Vladivostok area display Moscow Time, as that area is 7 hours ahead of western Russia, so this probably only refers to timetables for trains covering several timezones and where the start or finish is within the Moscow Time timezone.

The short article (only two sentences) about continental time states that "In the United Kingdom, continental time refers to a time-keeping system used on the mainland of Europe, either the 24-hour clock, or the Central European Time zone. The former usage has become rarer as the UK uses the 24-hour clock more." On it's talk page, someone has added in 2008 that this expression is rarely used, "but invariably refers to CET. It's a very long time since the 24 hour clock was perceived as a strange continental European habit!"

I've lived in the UK for 20 years, and I have on occasion heard CET being called "continental time", but I have never heard that expression being used for 24-hour notations, especially as 24-hour notations have been the UK norm for a long time in a growing number of areas, such as timetables (since 1964), and an increasing number of radio and TV schedules. It is also the norm for in-picture time display on most UK TV channels.

So, unless someone provides supporting references for this claim, it should be removed. Thomas Blomberg (talk) 10:41, 21 August 2011 (UTC)


 * I agree, especially about railway time, which I definitely understand to mean the idea of agreeing on the time between different cities, regardless of how that time is represented. I went ahead and removed the text. If someone disagrees, they are free to add the text back with an appropriate citation. Quietbritishjim (talk) 13:53, 21 August 2011 (UTC)


 * The terms are historical more than current. Back in the middle of the 20th century people occasionally referred to the 24-hour clock as 'the Continental method of expressing time' - see for example the debate in Hansard between PM Harold Macmillan and an MP (quoted in one of the references). I don't think it's worth inserting a historical reference at this point, it's not an important fact. As for railway time, this is more dubious, since railways didn't adopt the 24-hour clock as rapidly or consistently as they adopted standardised time - only in the mid 1960s in Britain, for example. (I think metric units and 24 hour time are still regarded as strange continental habits by many Britons 'of a certain age'... :) Cormullion (talk) 21:43, 21 August 2011 (UTC)

Should the 24 vs 12 hour table be listed in full?
Gratifying that it is to know that people are using the table, I'm not convinced that it is necessary to list every hour. I think the article would be better with the shorter version, enough to illustrate the principle. Does anybody else have an opinion on the matter? Mitch Ames (talk) 09:08, 11 April 2012 (UTC)

I did the original revert when I wasn't signed in a week or so back. I think having the full table there is very useful as a reference. Speaking from my point of view, I can usually convert in my head, but I always end up coming here just to make sure that I didn't mess it up. I have to do a lot of 24 hour GMT to 12 hour EST conversions, and having the full table really helps me. I guess I don't see WHY it should be removed, I haven't seen a good argument for it yet. rob3r (talk) 14:33, 11 April 2012 (UTC)


 * My reason for deleting the extra rows was that it takes up extra space, meaning I have to scroll more to read the actual text. Mitch Ames (talk) 12:10, 12 April 2012 (UTC)


 * I can understand that (less scrolling), but I do think that the full table helps as a teaching aid as well. Some people may just figure it out with the mini table, but for others I think seeing exactly how it works for every hour helps reinforce the theory. rob3r (talk) 15:38, 13 April 2012 (UTC)


 * Having all the hours does not add information and makes the table extend quite deep into the article. I'm intrigued by your conversion from GMT. What does GMT have to do with this article? How can this table help in that conversion? &minus;Woodstone (talk) 17:17, 12 April 2012 (UTC)


 * I disagree, I think the full table does add information, and useful information at that. GMT has nothing to do with this article in particular, it is just why I end up coming here so I mentioned it. I often get times in GMT that are in the 24 hour format, and I need to convert them to 12 hour EST. You'd think I'd have it memorized by now, but I always end up coming here for the table. rob3r (talk) 15:35, 13 April 2012 (UTC)

Countries have different practices whether or not the 24hr clock is spoken or only written
Any information on this? If I remember in Denmark, you are supposed to always *write* using the 24 hour clock, but spoken Danish used the 12 hour clock. What other countries do this?

http://www.fyidenmark.com/danish_time.html — Preceding unsigned comment added by 74.64.108.61 (talk) 02:36, 15 August 2012 (UTC)

Just as 12-hour clock
Someone preceded the description by:
 * "The time of day is written in the 24-hour notation exactly as in the 12-hour notation except that the numbers 13 to 23 (and sometimes 24) are also used (and AM and PM are not used)."

With several parenthetics, this is poorly written. It is also incorrect, and incomplete. It fails to say when 13 to 23 are used, and that 12 is not used for a.m. times. Why explain something sloppily in terms of something else instead of giving a clear description on its own? &minus;Woodstone (talk) 07:00, 22 August 2013 (UTC)

In the added part about pronunciation the reference is not a reference at all, just a supposition. &minus;Woodstone (talk) 07:00, 22 August 2013 (UTC)


 * And in pronunciation we might say "ten to four", but not "ten to sixteen". - David Biddulph (talk) 07:10, 22 August 2013 (UTC)

Time
The article seems to be written in such a way that tries to teach the reader how to use 24 hour time. Is there really an adult person in the western world who doesn't know how to use 24 hour clock? Certainly not in Europe. If there are such persons then this article should try to be more accessible to all readers rather than the select few.

Also it would be useful if the article made reference to extended time systems. For example, in Japan it is quite common to see times such as 25.30 (0130) and 27.30 (0330). This system is used in bars and clubs to show the night when an event is happening. 15 June at 25.30 would be useful as those who are planning a night out on the 15th would instantly know they can attend whereas saying 16 June 0130 might not be immediately recognized as being the night of the 15th. Seemed a bizarre system when I first saw it used but it caught on in the end.--217.71.45.42 (talk) 19:01, 12 June 2013 (UTC)


 * 24-hour clock mentions "Time-of-day notations beyond 24:00 (such as 24:01 or 25:59". Perhaps it should be moved out into a separate section. A reference would be good, if you have one. Mitch Ames (talk) 11:45, 13 June 2013 (UTC)


 * Perhaps a bit late, but some standards for exchange of transport schedules use hours over 24 if trips pass over midnight. See for example at: GTFS. &minus;Woodstone (talk) 10:58, 22 August 2013 (UTC)

Time and law
It's a nice article in theory, but needs a section on time and law, as to when the day legally starts and what marker, or mean, or standard, is employed to determine when this occurs. Historically days have begun and ended at noon, not midnight, because noon, not midnight, could be objectively determined. Which is still the case today.

For those of you on a 24 hour clock, do this: Go to your local hospital. Find the person in charge of birth records, and ask how they write 1:00 pm. 1:00 am.

The law differs from this, and it differs for reason. — Preceding unsigned comment added by 108.15.119.52 (talk) 19:48, 26 August 2013 (UTC)


 * If you provide links to reliable sources that describe this, someone may add an appropriate section. Remember that "law" varies between countries, so information about different countries would be good. (But even if we have references for a specific country, we can still include it, just noting that specific country.) Mitch Ames (talk) 13:15, 28 August 2013 (UTC)

Expressing 24 hour time in spoken English
It would be helpful if this article had a section on expressing 24 hour time out loud like this section in the Date format article. --108.206.97.137 (talk) 00:13, 15 May 2012 (UTC)

The article does explain how the time is spoken in military time, but does not explain the spoken method used in English speaking countries (excluding U.S.A.) This should be added somewhere. Simplicity rules (talk) 22:16, 31 January 2014 (UTC)