About isbnDecoder.com

isbnDecoder.com is a free ISBN (International Standard Book Number) decoder and validator. Paste any ISBN-10 or ISBN-13 and we'll decode the registration group, publisher prefix, title number, and check digit — and verify its structure against the ISO 2108 standard.

The site also includes reference pages for all ISBN registration groups (language/country groupings) and a publisher lookup tool based on International ISBN Agency registrations.

This site is operated by Long Pattern LLC. We build reference tools on top of published open standards and public datasets. isbnDecoder.com is not affiliated with the International ISBN Agency or any publisher.

Questions or corrections? Contact us.