ISBN Generator

How the ISBN identifies a book

The ISBN — International Standard Book Number is the worldwide identifier for monographic publications, created in 1970 and standardised as ISO 2108. It originally had ten digits (ISBN-10); since January 2007 every new ISBN is issued in the thirteen-digit format (ISBN-13) by prefixing the legacy block with 978 — and, when that range is exhausted, with 979 — so the number aligns with the EAN-13 barcode used in retail.

An ISBN-13 is made of four blocks plus a check digit: a 3-digit GS1 prefix (978 or 979), a 1-to-5-digit registration group (country or language area), a 1-to-7-digit registrant (publisher) element, a 1-to-6-digit publication element, and one check digit. The blocks have variable length but always add up to twelve identifying digits.

Check-digit math

For ISBN-13, multiply the first twelve digits alternately by 1 and 3 (positions 1, 3, 5… get weight 1; positions 2, 4, 6… get weight 3), sum the products, take the remainder modulo 10 and subtract it from 10; if the result is 10, the check digit is 0. It is the same formula as EAN-13. For ISBN-10, multiply the first nine digits by descending weights 10, 9, 8, 7, 6, 5, 4, 3, 2, sum them, take the remainder modulo 11; the check digit is that remainder, written as X when it equals 10.

Registration groups around the world

Some well-known groups: 0 and 1 (English-speaking area — USA, UK, Australia), 2 (French-speaking area), 3 (German-speaking area), 4 (Japan), 5 (Russia), 7 (China), 84 (Spain), 85 (Brazil), 88 (Italy), 972 (Portugal until 2007) and 989 (Portugal, current). In Brazil ISBNs are issued by the Câmara Brasileira do Livro (CBL) in partnership with the Biblioteca Nacional. Each format — print, e-book, audiobook — needs its own ISBN; the identifier is tied to the edition, not to the title.

When ISBN is not the right code

ISBN only covers books and monographic publications. Periodicals (magazines, journals, newspapers) use ISSN; printed music uses ISMN; films and audiovisual works use ISAN; sound recordings carry an ISRC per track and a barcode UPC/EAN per release.

FAQ

Can I use a generated ISBN on my own book? No. To publish you must request a real ISBN from the official agency in your country (CBL in Brazil, Bowker in the USA, Nielsen in the UK). A generated number is only a mathematically valid placeholder.

Is the output a real ISBN? The check digit is correctly computed by the ISO algorithm, so it passes every validator — but the prefix/group/registrant combination is random and is not registered in the official ISBN database.

What is it useful for? Mock catalogue data, unit tests on library systems, e-commerce form validation, training datasets and UX prototyping.

Does the tool send my data anywhere? No. Generation runs entirely in your browser with JavaScript — nothing is transmitted to the server.