Wikipedia talk:Age calculation templates

This page contradicts information found in templates such as Template:Death date and age. This page states "For deceased people, the raw numbers should be used instead to avoid over use [sic] of templates." The template pages, however, imply that age templates should always be used to improve metatdata.

Might also the death age templates be included here?

Shamatt (talk) 17:52, 22 April 2008 (UTC)


 * Interesting. My suggestion to use raw numbers was to save on processing, but if they are doing something useful with the death templates, by all means use them.  --Arctic Gnome (talk • contribs) 19:20, 22 April 2008 (UTC)

Extra information
Any chance there could be a template which outputs hours/mins/secs lived? :-p -- Menti  sock  14:46, 28 November 2008 (UTC)
 * Agreed, there is a table I am working on has length of title reigns. The problem is there are a couple of title reigns that are less than 1 day.  TJ   Spyke   17:32, 19 December 2008 (UTC)

Birth/death date template mergers
See Wikipedia:WikiProject Time. —bender235 (talk) 13:52, 9 October 2010 (UTC)

Template revision from month, day year to year, month day
I realized that several of these templates use input parameters in the following order: month, day, year. As the US is the only country in the world which only uses this format (Canada uses a mix of mm/dd/yyyy and dd/mm/yyyy), I propose these templates to be moved to "template_name"_US and create identical templates using the following format exclusively: yyyy/mm/dd. This will allow consistency between age calculation templates and consistency with world wide date formats (ISO 8601). To list a few, here are the templates which are currently using the US date format:
 * 24 years, 6 months
 * 8945 days

Xionbox₪ 11:57, 12 April 2011 (UTC)

Possible widespread distribution of bad data based on age-calc templates
Correct me if I'm wrong, but from what I've just been reading at List of longest-reigning British monarchs, List of longest reigning monarchs of all time, Template:Age in years and days, Template:Age in days, Template:Gregorian serial date, and here, there is probably quite a bit of inaccuracy spread throughout Wikipedia wherever editors are using our age-calculation templates to state late-2nd-millennium ages (or reign lengths, or any other number-of-days measurement). These use the Gregorian calendar, which is fine for time periods solely before 1582 or solely after the early 20th century, but run into complex turbulence for many measurements that include the years between. According to Gregorian calendar, it took about 350 years for nations around the world to switch to Gregorian (at least for secular and/or global date-keeping), meaning that 10–13 days dropped out of different countries' calendars at different times.

It'd be a challenge to fix these templates to correct country-specific errors. At List of longest-reigning British monarchs, the reigns of George I (1714–1727) and George III (1760–1820) have accurate day-counts, but George II's (1727–1760) is off by 11 days. Any similar use of day-counts when talking about Philip II of Spain (1527–1598), Frederick IV of Denmark (1699–1730), Emperor Meiji of Japan (1867–1912), etc. – but neither their predecessors nor their successors – would likewise be incorrect. And it can get much worse: the first and last Acadian governors' terms apparently overlapped a switch to Gregorian in 1605 and back to Julian in 1710 (when Britain captured Nova Scotia, but before the British themselves switched).

Anyway, I see at least four possible fixes here:
 * 1) Make some incredibly sophisticated template tweaks that account for lost days depending on the country and date range.
 * 2) Add an extra Gregorian-adjustment parameter that requires editors to look up (and source!) the number of days subtracted due to the local calendar change.
 * 3) Add some kind of facility to flag each date used to calculate ranges as pre- or post-change, with a calculation complexity somewhere between (1) and (2).
 * 4) Establish a policy to avoid the use of age-calculation templates entirely, due to the false sense of accuracy they provide in some cases.

I think I'd favor (2) because it'd be far simpler to execute and still be usable by article editors. Anything but (4) should include a policy that the date style used has been identified and confirmed by a reliable source. (Oh, another point! I'd forgotten that there's also the question of Old Style and New Style dates, reflecting a change of "New Year" to "1 January", not necessarily contemporaneous with the Julian-to-Gregorian change. We must ensure our date sources means the same year we think they do when they say something like "30 January 1648" – Old Style's date would mean 30 January 1649 to us New-Style users.)

I brought this issue up here because this Wikipedia essay is currently considered an "orphan"; i.e., not referred to by many (if any) project pages. On the contrary, this essay (or something like it) must clearly indicate how to avoid these problems when using age-calculation templates. ~ Jeff Q (talk) 01:02, 25 July 2011 (UTC)


 * I don't think we need to add a parameter to adjust for the calendar change. We do have to make sure that calculation templates use the same calendar on both ends of the calculation and that we mention in text that the calendar changed. The infobox of George II of Great Britain does this right; it gives his birth date in both calendars but the template that calculates his age at death only uses the new calendar for the calculation. —Arctic Gnome (talk • contribs) 03:40, 25 July 2011 (UTC)

Can't find the right template for exact birth date and approximate death date
Maria Koepcke was in a plane that crashed on Christmas Eve 1971. It is known that she survived a few days, but her exact date of death is not known. The article gives her date of death as 24 December, but that is not correct. I've been looking at templates, and there doesn't seem to be one for a case where the exact birth date is known but the exact date of death is not. "December 1971" converts to "December 1971" but since the article says she was born on 15 May 1924, it seems silly to state that she was aged 46-47 when she died.

Can anyone help? Girlwithgreeneyes (talk) 22:18, 18 June 2013 (UTC)

Boundary condition for age on birthday
If you look at a biographical entry for a figure on their birthday, it won't show their new age until that day has fully passed. In the US (I don't know if this is different elsewhere), if you ask someone on their birthday, how old are you?, they will tell you their new age. Further, that threshold (the very beginning of the day) is honored in other contexts.

And, if you look someone up on their birthday, you will find their age is not fresh quite yet. While in the media, you'd hear — so and so is n today.

I tried a succinct comment about this for that oft-used template, but it was reverted without comment.

24.217.99.176 (talk) 20:17, 22 July 2021 (UTC)
 * My edit (diff) included a reason. At birth date and age, see the "Is the displayed age incorrect?" box near the top. The problem applies to all time and date functions—unless they are shown with JavaScript that runs on your computer at the time you view the page, the time/date will be as calculated when the underlying HTML page was last generated. Wikipedia uses a system of caching servers that feed prepared HTML pages to people viewing pages. When a time/date is wrong, someone needs to purge the page. The simplest method is to edit the whole article where the problem appears but don't change anything. Don't enter an edit summary. Click Publish to save the edit (even though you did not change anything). The edit will not appear in history but it will cause the HTML to be regenerated which will cause times and dates to be recalculated. That explanation is also at Template talk:Birth date and age and its archives. Johnuniq (talk) 00:13, 23 July 2021 (UTC)