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ISBN (International Standard Book Number)

What is the ISBN?

The ISBN is a unique machine-readable identification number for books and is defined in ISO Standard 2108. The SBN (Standard Book Number) was first used in the UK in 1969, and the international standard was established in 1972.

The ISBN was originally defined as a ten-digit number. The numbers still available for allocation are, in some areas, running low. In revising the standard to increase capacity, the ISBN Revision Working Group took the opportunity to align the ISBN with the EAN global article numbering system. Following an international review process, the standard has been revised to a 13-digit number, which will be used from 1 January 2007. Further information on the changeover can be found at:


The number consists of ten digits, divided into four parts of variable length. The number must be separated clearly by hyphens or spaces when printed, and be preceded by 'ISBN'. However, when stored in catalogue records, the hyphens and spaces are often omitted. The final digit is a check digit and can be any of the numerals from 0 to 9 or an upper case X.

0Group identifier
571Publisher identifier
08989Title identifier
5Check digit

E.g. ISBN 0 571 08989 5 or ISBN 0-571-08989-5


The new ISBN-13 will be identical to the EAN code for books. At present when a barcode is applied to the publication (as required for retail systems), the 10 digit ISBNs are converted into a 13-digit EAN code (sometimes referred to as the 'Bookland EAN') by adding a 3-digit product code for books (978) in front of the ISBN and then recalculating the check digit to take account of the extra 3 digits. To expand the capacity of the ISBN system, another product code (979) has been assigned for books, providing a new range of numbers.

ISBN: 0-901690-54-6
EAN: 978-0-901690-54-8

EAN-UCC is the International Article Code; this is a system for assigning unique identifiers to products for the retail trade. Originally the European Article Number code system, in January 2005, the Uniform Code Council (UCC) will begin migrating the US 12 digit Universal Product Code (UPC) to the UCC/EAN international standard. More information about the EAN-UCC product code system is available at the EAN International web-site at:

International ISBN Agency

Notes on use

Moving from ISBN-10 to ISBN-13

  • ISBN-13 will be in use from 1st January 2007 but may appear on items and in catalogue records before that date.
  • Publishers, distributors, retailers, libraries and any other organisations that record and exchange ISBN data in their automated systems will need to ensure their systems can accommodate the new 13-digit ISBN.

When does a work need a new ISBN?

  • The work is produced in a new format (e.g. hardback, paperback, electronic text).
  • There is a (substantial) change of text. The title page should state that it is a revised edition.
  • There is a change of title of the work.

When does a work not need a new ISBN?

  • The price of the work changes.
  • The work is reprinted.

An ISSN can be assigned to a series of monographs. Each individual monograph will have its own ISBN.

Once allocated, ISBNs are not re-used, to avoid confusion.

Recording an ISBN in MARC 21

ISBNs should be recorded in field 020 ISBN

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Content by: Ann Chapman of UKOLN.
Page last revised on: 08-Jun-2005
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