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Inside WorldCat

WorldCat consists of three components: a bibliographic catalog, a knowledge base, and a registry for library information.

 

icon for the WorldCat bibliographic catalog

The worldwide catalog of library resources

The WorldCat bibliographic catalog includes everything that’s available to users in the library. Beyond books and print journals, the catalog of physical materials includes DVDs, historic photos, video games, musical scores, newspapers, webpages and many other standard items. It also includes unique items, such as 2,700-year-old jewelry and Soviet civilian medals.

In 1971, librarians in Alden Library at Ohio University added the first bibliographic records to what was then known as the OCLC Online Union Catalog. Within eight years, the catalog already included more than five million records. Now known as WorldCat, the catalog today includes millions of records and billions of holdings.

As the WorldCat bibliographic catalog continues to grow in quantity, efforts to improve the quality also increase. Professional catalogers all over the world consistently improve WorldCat records to make them as complete and useful as possible. This cooperative resource simplifies cataloging, maintenance, interlibrary loan and discovery tasks for libraries worldwide.

Learn more about WorldCat data quality

How WorldCat evolves

WorldCat has continued to keep up with the way modern library users prefer to consume media. From print books to streaming video and beyond, you can find it in WorldCat. Here are a just a few of the many formats that have been added to WorldCat over the years.

WorldCat launches with:

Books

Theses

Atlases

Articles

Musical scores

1971

Serials

Photos/Images

Films

Audio cassettes

Sound recordings

1975

Newspapers

Computer files

1980

Floppy discs

1986

Audio CDs

1987

CD-ROMs

1996

DVD-ROMs

2000

Streaming video

2008

Blu-ray discs

Italicized years are approximate

Scott Seaman [photo]

“The world’s knowledge…”

“Modern scholarship would not have been possible without the creation of WorldCat. … To have the world’s knowledge cataloged and made available has just been an extraordinary miracle. And to have been the first contributor is almost unthinkable. It’s such an honor.”

Scott Seaman
Dean of Libraries, Ohio University
Athens, Ohio, United States


Vital statistics

WorldCat growth

Number of bibliographic records

534,131,847 (as of December 2021)

Number of holdings

3,218,456,426 (as of December 2021)

+3.54%

Bibliographic records

+3.48%

Holdings

+10.16%

Local holdings

+6.39%

Local bibliographic data

(December 2020–December 2021)

WorldCat gets more than one new record

every second

Members fill an ILL request

every second

Watch WorldCat grow.

Watch in real time as librarians and information service professionals from all over the world contribute records to WorldCat.

Language composition of WorldCat items

Non-English

61%

English

39%

(as of December 2021)

Number of languages

483 (as of December 2021)

More language statistics

Top 10 languages

English

39%

203 million

German
12%

63 million

French
9%

47 million

Spanish
5%

25 million

Chinese
3%

16 million

Japanese
3%

13 million

Italian
3%

13 million

Polish
2%

8 million

Russian
1%

8 million

Dutch
1%

8 million

(as of December 2021)

1+ million records

  • Latin
    6.9 million
  • Swedish
    6.1 million
  • Danish
    4.3 million
  • Portuguese
    3.3 million
  • Arabic
    3.3 million
  • Hebrew
    2.9 million
  • Korean
    2.7 million
  • Slovenian
    2.6 million
  • Czech
    2.0 million
  • Hungarian
    1.7 million
  • Catalan
    1.5 million
  • Thai
    1.4 million
  • Finnish
    1.2 million

500,000–1 million records

  • Romanian
    921,000
  • Turkish
    905,000
  • Indonesian
    823,000
  • Ukrainian
    809,000
  • Norwegian
    682,000
  • Greek, Modern (1453-)
    682,000
  • Croatian
    639,000
  • Malay
    534,000
  • Serbian
    507,000

250,000–500,000 records

  • Persian
    497,000
  • Vietnamese
    435,000
  • Afrikaans
    388,000
  • Hindi
    339,000
  • Bulgarian
    328,000
  • Yiddish
    323,000
  • Greek, Ancient (to 1453)
    299,000
  • Tamil
    298,000
  • Welsh
    278,000
  • Urdu
    251,000

100,000–250,000 records

  • Frisian
    220,000
  • Slovak
    213,000
  • Basque
    208,000
  • Norwegian (Bokmål)
    187,000
  • Lithuanian
    160,000
  • Bengali
    156,000
  • Sanskrit
    131,000
  • Galician
    130,000
  • Icelandic
    124,000
  • Armenian
    117,000
  • Tibetan
    104,000

Scripts represented in WorldCat

Non-Latin scripts represented in WorldCat

37

(as of December 2021)

Top 10 non-Latin scripts

CJK
72.78%

31 million

Arabic
7.82%

3.3 million

Cyrillic
7.64%

3.2 million

Hebrew
6.92%

2.9 million

Thai
2.86%

1.2 million

 

Greek
1.30%

549,000

Tamil
0.21%

91,000

Armenian
0.16%

66,000

Devanagari
0.10%

41,000

Bengali
0.02%

 

icon for the WorldCat knowledge base

A knowledge base to connect users to e-resources

The WorldCat knowledge base connects library users to the electronic content provided by their library. It combines data about a library’s e-resources with linking features that make the collections easier to find, share, manage and use. Like data in the WorldCat bibliographic catalog, knowledge base data are not tied to a particular application, so libraries can streamline electronic content workflows across multiple systems.

The WorldCat knowledge base’s cooperatively maintained collections continue to grow with content from libraries and publishers from around the world. Because OCLC is a non-profit, vendor-neutral cooperative, the WorldCat knowledge base is the only source that includes records from both EBSCO and ProQuest, Gale and Springer, and Wiley and Elsevier, among many other content suppliers.

Logos of some of our partners in the WorldCat knowledge base: ProQuest, EBSCO, Elsevier, Springer, Taylor and Francis, McGraw Hill Education, Wiley, Ingram, Cambridge University Press, Gale Cengage Learning, ebrary, Oxford University Press.

The knowledge base also includes free and open-access materials that users can find and get alongside their library’s materials. As of December 2021, the knowledge base provides access to more than 57,875,654 records and 20,776 content collections from 631 providers. Download an Excel spreadsheet that lists all knowledge base collections to see what’s available today.

Download a white paper on e-resource challenges

Sharing holdings to improve discovery

Maurine McCourry [photo]

“Drastically improved discovery…”

“We have title-level OCLC cataloging for most of our subscribed databases, which is amazing. ...It has drastically improved discovery.”

Maurine McCourry
Technical Services Librarian
Hillsdale College
Hillsdale, Michigan, United States

 

icon for the WorldCat registry

A registry of library profiles to increase visibility

The WorldCat registry allows libraries to maintain information about their services and contacts to help information seekers find the library online. When librarians maintain their institution’s location, hours, relationships, services and contact information, the WorldCat registry populates that information on WorldCat.org and elsewhere through links on popular websites. Library staff can also share profiles with vendors and consortium members to ensure they always have the most accurate contact information.

Visit the WorldCat registry

Find in a Library links

Services across the internet help people find great books to read. The WorldCat data embedded into those websites through “Find in a Library” links help direct readers to libraries near them that hold the book they want. The WorldCat registry provides the location and other information needed to connect libraries with readers.