ISBN Validator & Generator

Validate International Standard Book Numbers (ISBN-10 and ISBN-13) using official check digit algorithms. Generate valid ISBNs for library systems and book databases.

ISBN Validator

Enter ISBN-10 or ISBN-13

ISBN Standards

ISBN-10: Older format used until 2007. Consists of 10 digits (the last can be 'X'). Uses a weighted sum mod 11 checksum.

ISBN-13: Current standard. Consists of 13 digits starting with 978 or 979. Uses a weighted sum (1, 3, 1, 3...) mod 10 checksum.

ISBN Generator

Disclaimer: Generated numbers are mathematically valid but may not correspond to actual published books.

What is an ISBN?

The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Each ISBN is assigned to each separate edition and variation of a publication.

Check Digit Calculation

The check digit is the last character of the ISBN. It is used to verify that the ISBN has been correctly entered. ISBN-10 and ISBN-13 use different mathematical formulas for this calculation.

The 978/979 Prefix

ISBN-13 numbers always begin with either 978 or 979. These are the "Bookland" EAN prefixes that signify the item is a book in the EAN-13 barcoding system.