UDC Online Hub is a platform providing access to complete and most recent UDC schedules in multiple languages based on a collaboration between the UDC Consortium and UDC publishers in different countries. UDC Hub was released in August 2013 by UDC Consortium (The Hague), who owns the copyright and maintains the Universal Decimal Classification (UDC) scheme.


UDC Online English

Publishing date:26 August 2013
Current version:UDC MRF12 (last updated January 2019)
Publisher & Copyright:UDC Consortium
UDC Publication Number:093
Editor-in-ChiefDr. Aida Slavic, PhD
Suggestion for citationUDC Online English. Version UDC MRF12. The Hague: UDC Consortium, 2019. (UDCC Publication: 093). [accessed: YYYY-MM-DD]. Available at: https://udc-hub.com/en/login.php.


The English UDC Online is a complete standard edition of the scheme on the Web containing more than 72,000 classes extended with over 12,000 records of historical UDC data (cancelled numbers). This online tool offers a number of functions to facilitate searching, browsing, parsing, validating, filing and building of UDC numbers. Searching and viewing of historical data is intended to help users in tracing cancelled numbers and their redirections that may still exist in library collections.

Who should use UDC Online?

UDC Online is a professional indexing and classification tool intended for UDC specialists in libraries and other bibliographic and information services. It is a UDC reference tool and is independent of any local indexing policies and principles that may guide the application of UDC. Although this is a user friendly tool, with many notes and instructions assisting indexers, it assumes that users are professionals familiar with UDC and document content indexing.


The system is driven by the UDC Master Reference File database, maintained in English and regularly updated and maintained by the UDC editorial team at their headquarters in The Hague. The UDC Online is updated periodically based on changes published in the Extensions and Corrections to the UDC and released in the subsequent version of the UDC Master Reference File (UDC MRF). The last UDC MRF update is issued in December 2018.

Ownership and maintenance

The system is created, maintained and run by the UDC Consortium in The Hague, who owns the copyright on the UDC Content and its versions in English language. This has many advantages for users as they will be supported by a team of UDC specialists working on UDC content and maintaining the UDC database.

User support

User support for English is provided by the UDC Editorial Team.

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