ISBN check

ISBN output language:

ISBN (International Standard Book Numbers) are 10-digit numbers (from 2007: 13-digit numbers) defined in the ISO 2108 standard. They are unambigous identifiers for books and other nonperiodic media. The assignment of ISBNs is coordinated by the International ISBN Agency. This agency assigns certain number ranges to national/regional ISBN agency (such as the UK ISBN Agency (UK and Ireland) and R.R. Bowker LLC (USA). Publishers apply to these national/regional agencies for the ISBN that they need.

The form on this site allows you to check an ISBN for consistency using the built-in checksum. If the check shows that the number that you input was not a valid ISBN the site offers you a list of possible correct ISBNs (from which the incorrect number could have resulted by changes or transposition of digits or by dropping/adding a digit), and the output allows you to search for these possible ISBNs in databases of some booksellers' sites. (note: variants checking available for ISBN-10 now; will be expanded to ISBN-13)

The standards committee for ISO 2108 has expanded the ISBN format from the present 10 digits (ISBN-10) to 13 digits (ISBN-13) effective 1 January 2007 to prevent the system running out of numbers.

Further research resources on books and ISBN: catalog of the Library of Congress (USA), the catalog of the French National Library and Books by ISBN.

Responsible for this site: Tomas Schild, Martha-Schmidtmann-Str. 4, 70374 Stuttgart, Germany, <>. In cooperation with