About Universal Decimal Classification

** UPDATE **

22 July 2013

BSI and UDC Consortium announce UDC Online replacement service

English speaking users of UDC will be able to access a new UDC Consortium's UDC Online service from 26 August as BSI’s UDC Online will be closing from 1 October 2013. The upgraded UDC Online service offers improved searching and browsing functions and several new features such as access to cancelled numbers and alphabetical chain index.

The new product is a part of the multilingual UDC hub-service driven directly from the UDC Master Reference File (MRF) database and run by the UDC Consortium (The Hague). The new online service has been developed to bring together and align existing translations with the regularly updated knowledge content of the UDC. The tool aims to provide a better, up-to-date and more convenient service for users world-wide. The English version will be the first edition to be made available online.

The UDC was created in 1900s and it has since been used in over 150,000 libraries and other information services in over 130 countries. It is one of the most sophisticated and most widely used knowledge organization schemes in the world.

BSI, the business standards company is a global independent business services organization that inspires confidence and delivers assurance to over 70,000 customers in 150 countries with standards-based solutions. BSI has been the principal publisher of UDC schedules in English since the 1930s and a member of the UDC Consortium from 1992-2012. BSI's expert input into the UDC development for over 70 years has been invaluable for UDC users in many countries.

High quality printed BSI UDC editions are appreciated by documentation specialists worldwide. In spring 2001, BSI released a web version of the English UDC schedules called "UDC Online" - the first of its kind in the bibliographic domain. BSI UDC Online was at the forefront of online classification schemes and has been serving users for over 10 years.


Universal Decimal Classification (UDC) is the world’s foremost classification scheme for all fields of knowledge, used for sophisticated indexing and retrieval. It is based on the Dewey Decimal System, but uses auxiliary signs to indicate various special aspects of a subject, and the relationships between those subjects.

UDC has been modified and extended over many years to cope with the increasing output in all disciplines of human knowledge. It is still under continuous review to take account of new developments.

The documents classified by UDC may be in any form. They will often be literature, i.e. written documents, but may also be in other media such as films, video and sound recordings, illustrations, maps, and realia (real-life objects) such as museum pieces.
Since first published over 100 years ago, UDC has developed into a highly flexible and effective system for organizing bibliographic records for all kinds of information in any medium, and is used internationally by:

  • Libraries
  • Museums archives
  • Bibliographies
  • Bibliographic databases
  • Information services
  • nternet.

The design of UDC lends itself to machine readability, and the system has been used both with early automatic mechanical sorting devices, and modern library OPACs.

A core version of UDC, with 65,000 subdivisions, is available in database format, and is called the Master Reference File (MRF). The current full version of the UDC has 220,000 subdivisions.

Free two week trial of UDC Online
For the trial please contact our UDC Customer Services department on +44 345 086 9001, email at udc@bsigroup.com.

Read more about the Universal Decimal Classification

Read more about the structure and use of Universal Decimal Classification structure
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