Wikipedia:Size comparisons

This article compares the size of Wikipedia with other encyclopedias and information collections.

Source material from which Wikipedia statistics in this article are derived is available; the Footnote on WikiStatistics section at the end of this page provides technical discussion of this article.

Wikipedia
Currently, the English Wikipedia alone has over articles of any length, and the combined Wikipedias for all other languages greatly exceed the English Wikipedia in size, giving more than 29 billion words in 55 million articles in 309 languages. The English Wikipedia alone has over 4.3 billion words, and has over 95 times as many words as the 120-volume English-language Encyclopædia Britannica (online), and more words than the enormous 119-volume Spanish-language Enciclopedia universal ilustrada europeo-americana.

In 2005, the English-language Wikipedia more than doubled in size, and many smaller Wikipedias have grown by a higher multiple.

In June 2011, there were more than 11 million articles in all Wikipedias and 3.6 million in the English version.

Wikipedia is still in need of much expansion and improvement. Many of the articles are of poor quality and some mainstream encyclopedia topics are not covered adequately. In addition, the average article length is only a little over half the size of that in Encyclopædia Britannica, although many major articles are considerably longer. Over time the balance of the editorial effort is expected to slowly tilt towards a greater emphasis on increasing the quality, scope, classification and interlinkage of existing articles. However, new articles will probably always be created in large numbers, as Wikipedia's conventions on acceptable article topics incorporate huge numbers of potential new articles every year (newly prominent people, current events, media products, physical products, etc.). In mid-2006, the rate of new article creation was still rising, but only slowly. , it looked as if the rate of article creation may have peaked in mid-2006, though subsequent analysis may show otherwise. See Modelling Wikipedia's growth for more on Wikipedia's growth rate and expected future size.

Other online encyclopedic resources
There are many other online databases which combine several encyclopedias and encyclopedic dictionaries and allow users to search all of the works simultaneously. One example is Oxford Reference Online—a database of 221 encyclopedias and encyclopedic dictionaries, offering about 1.4 million articles, with expansions planned for the future. Another example is Xrefplus, which offers access to 262 encyclopedias, dictionaries, and other reference books. This all added up to about 2.9 million entries when the database had 225 titles. There also is HighBeam Research and GaleNet. GaleNet—which is likely the largest named so far—offers users the ability to search several encyclopedia databases, including the Biography Resource Center (1,335,000 people), Gale Virtual Reference Library (594 reference books), and the Science Resource Center (51 titles), among others.

Paper encyclopedias
The largest paper encyclopedia ever produced is possibly the Yongle Encyclopedia, completed in 1407 in 11,095 books, 370 million Chinese characters and commissioned by the Yongle Emperor. The individual books that made up the encyclopedia were small by modern standards; the work was twelve times the size of the 20 million word French Encyclopédie, giving 240 million words, or 21,600 words per book, although it is unclear if that is how it differs from the Encyclopédie in size. It is also unclear if it is twelve times larger than the original 28-volume version of the Encyclopédie completed in 1772 or the 35-volume version completed in 1780. The Yung-lo ta-tien was a collection of excerpts and entire existing works, rather than an original work. Only two copies were made and all that survives is a small fraction of one copy.

Comparison of encyclopedias
Numbers regarding total characters are based on an estimated average word length of five, plus a space, or six characters per word.

* Classical Chinese is a very compact language. The result is very short articles for the same content.

†It is said that the Yongle Encyclopedia is larger than the Complete Library of the Four Treasuries, but it is uncertain how they were compared.

‡Kenneth F. Kister, Kister's best encyclopedias: a comparative guide to general and specialized encyclopedias, (1994) p. 450. [Article count is for the 82-volume edition, rather than the 119-volume one.]

§Alfieri, G. Treccani Degli. "Enciclopedia italiana" Diccionario Literario (2001 HORA, S.A.)


 * Number of encyclopedic articles. The Nationalencyklopedin totals 356,000 entries.

††Kister, op. cit., p. 365.

** Includes 10,000 historical archives.

‡‡Advertised as containing "over 63,000 articles...with 36,000-plus map locations, and over 29,000 editor-approved Web site links." The 2006 Premium CD-ROM had 68,000 articles.

⁑Advertised as containing 41,500 articles written by 6,803 authors, 60 million of words, 350 million of characters, 360,000 links, 122,000 definitions in the included dictionary, 130,000 bibliographical references.

Size of other information collections
Note that Wikipedia is neither a dictionary nor a web index; these figures are just for order-of-magnitude comparison.

Astronomy

 * The Guide Star Catalog II has entries on 998,402,801 distinct astronomical objects searchable online.

Biology

 * The World Resources Institute claims that approximately 1.4 million species have been named, out of an unknown number of total species. A 2011 study says there are 8,700,000 species (6,500,000 land species, 2,200,000 marine species).

Chemistry

 * , over 227 million CAS registry numbers have been allocated for chemical compounds.
 * The Beilstein database claims entries on "8 million organic and 1.4 million inorganic and organometallic compounds".
 * The Merck Index Subscription Edition has over 10,000 monographs on chemical compounds.

Film and television

 * , The Internet Movie Database has records on 8,313,921 titles and 11,262,925 names.

Genetics

 * Each human being is estimated to have 20,000 to 25,000 genes.
 * Online Mendelian Inheritance in Man has over 25,000 entries, each describing a known gene,.
 * GenBank, an online database of DNA sequences from over 260,000 species, has over 110 million entries (sequence records) covering over 100 gigabases.

Geography

 * Ordnance Survey MasterMap (official site) is a record of every fixed feature in Great Britain, in a continuous digital map. Each of the 440 million fixed geographical features has a unique TOID (TOpographical IDentifier).
 * The National Geospatial-Intelligence Agency (NGA) (https://www.nga.mil/) GEOnet Names Server contains approximately 3.88 million named geographical features outside the United States, with 5.34 million names.
 * , the USGS Geographic Names Information System claims to have over 2 million physical and cultural geographic features within the United States.
 * , GeoNames contains over 25 million geographical names and consists of 11.8 million unique features whereof 2.8 million populated places and 5.5 million alternate names.

Internet

 * Over 25 billion web pages with over 1 trillion unique URLs were known to Google on February 24, 2006.
 * Netcraft logged roughly 40.5 million distinct websites in January 2018.
 * , the DMOZ web index claims to have over 1 million categories for over 5 million websites.
 * , Internet Archive claims to have indexed over 150 billion pages, +548,000 moving images, +82,000 concerts, +948,000 recordings and +2,945,000 texts.

Language

 * The Oxford Dictionary of English (formerly The New Oxford Dictionary of English) claims 355,000 definitions, and four million words of text.
 * The Oxford English Dictionary, Second Edition claims 301,100 definitions (with 616,500 word forms defined), and 59 million words of text.

Law

 * American Jurisprudence, Second Edition, is a 231 volume collection of American common law.
 * Black's Law Dictionary, Eleventh Edition, has 55,000 common law legal terms.
 * The Encyclopedia of Law has 105,000 legal entries.

Libraries

 * The British Library is known to hold over 170 million items.
 * The Library of Congress claims that it holds approximately 167 million items, 14 million of which are electronically searchable.
 * Copac is a searchable electronic catalogue of over 40 million books held in libraries in the United Kingdom and Ireland (includes all electronic records from the British Library)

Music

 * The freedb database holds information for nearly 2 million compact discs. Many of the disks are duplicates, however, so the number of unique CDs is unclear.
 * The AllMusic database contains entries for over 3 million releases, and over 30 million tracks as of.
 * The New Grove Dictionary of Music and Musicians, Second Edition, claims "25 million words with over 29,000 articles" about the subject of music alone.
 * , Jamendo project contains over 50,000 free and open albums.

People

 * Thomson-Gale's Biography Resource Center contains over 1,335,000 biographies. 335,000 are essays, while over a million are thumbnail entries.
 * The Oxford Dictionary of National Biography has over 50,000 articles on famous Britons, in 50 million words (implying an average article size of 1000 words).
 * The old British Dictionary of National Biography had over 50,000 articles in 50 million words.

Science and technology

 * The Espacenet free online service contains records on more than 90 million patent publications from the European Patent Office patent databases.
 * The Inspec database contains over 17 million abstracts.
 * The Ei Compendex database contains over 18 million records.
 * The Elsevier Biobase database contains over 4.1 million records.
 * The IEEE Xplore database contains over 4.5 million records.

The cost of a printed Wikipedia
The Print Wikipedia project published all of the English Wikipedia text, without photos, as of 2015 in 7473 volumes with 700 pages each (5.2 million pages in total). Lulu is willing to sell each volume for US$80, and the whole set for US$500,000.

, there were approximately 23 billion characters. Assuming 5,000 characters per page that would yield 4.6 million pages. If you then add 25% for extra space for photos, tables, and diagrams, that would yield 5.75 million pages. This would produce 14,375 volumes of 400 pages each. As an example, allowing US$0.05 per page would yield a cost of US$287,500 without binding.

Footnote on Wikipedia statistics
Very detailed statistics for almost all aspects of Wikipedia are available from https://stats.wikimedia.org/EN/Sitemap.htm.

Statistics for this page are taken from the Article count (alternate) table and from the Words table.

Excluding redirect pages, there are roughly (using figures from September 1, 2006):
 * 1.4 million articles that have at least a single link.
 * 1.3 million articles that have at least a single link and 200 readable characters (roughly equivalent to at least 33 words).

Taking the difference of these two figures, there are about:
 * 100,000 articles that have at least a single link but fewer than 200 characters.

There is also an uncounted number of articles which have no links. The current statistics provide no indication of the size of this last category. The 609 million words in fact span the 1.3 million bona fide articles, the remaining 100,000 linked articles, and the unknown number of articles without links. A rough estimate of the word count in the latter two categories is ten million words. Dividing the remaining 600 million words by 1.3 million gives a mean article length of about 460 words.

Further, of the articles on the English Wikipedia, perhaps 36,000 are "data dumped" gazetteer entries about towns and cities in the United States. It is controversial whether gazetteer entries should count towards the number of "real" encyclopedia articles; however, their statistical significance is very much less now than in October 2002 when they were added. Very many have been colonised by Wikipedians who have transformed them to varying extents, in some cases to an unimpeachably encyclopedic status.