ISBN and EAN-13 Check Digit Validator and Converter
Enter an ISBN or an EAN / JAN code to verify its check digit and convert between ISBN-10 and ISBN-13. If the last digit is missing, the tool calculates it for you. Hyphens and spaces are fine. Everything runs in your browser, and nothing you type is sent to a server. To turn a verified code into a barcode image, use the Barcode Generator.
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Accepts ISBN-10 (9-10 digits), ISBN-13 / EAN-13 (12-13 digits), and EAN-8 (7-8 digits). You can leave off the final check digit.
Result
Notes
- A valid check digit does not prove the code is assigned to a real book or product. It only catches typing errors.
- Inputs of 9, 12, or 7 digits are treated as missing the check digit, and the last digit is calculated. Inputs of 10 (ISBN-10) or 13 (ISBN-13) digits have their last digit verified.
- An ISBN-13 starting with 979 has no ISBN-10 equivalent. Converting ISBN-13 to ISBN-10 works only for the 978 prefix.
- Hyphen positions depend on registrant range tables per country and publisher, so the output is shown without hyphens.
Glossary
ISBN
The International Standard Book Number that identifies a book edition. It has had 13 digits (ISBN-13) since 2007; earlier books used 10 digits (ISBN-10).
EAN / JAN
The retail product barcode number (called JAN in Japan). It comes in 13-digit and 8-digit forms, and the last digit is the check digit.
Check digit
A verification digit calculated from the other digits. ISBN-10 uses weights 10 to 1 with modulo 11; ISBN-13 and EAN use alternating weights of 1 and 3 with modulo 10.
Bookland (978 / 979)
The prefixes reserved so that book ISBNs can be shown as EAN-13 barcodes. Only 978 has matching ISBN-10 numbers.
FAQ
What does the "X" at the end of an ISBN-10 mean?
The ISBN-10 check digit is derived from a remainder when dividing by 11. When the remainder is 10, the Roman numeral X is used instead of a digit. Lowercase x is accepted and treated as uppercase.
How are ISBN-10 and ISBN-13 converted?
To go from ISBN-10 to ISBN-13, put 978 before the first 9 digits and recalculate the check digit. To go back, take the 9 digits after 978 and add the ISBN-10 check digit. ISBN-13 numbers starting with 979 have no ISBN-10 equivalent.
What happens if I enter a code without its last digit?
Inputs of 9 digits (ISBN-10), 12 digits (ISBN-13 / EAN-13), or 7 digits (EAN-8) are treated as having no check digit, and the tool calculates it. Any other length produces an error.
Does a valid check digit mean the book or product exists?
No. The check digit only detects typing and scanning errors; it cannot tell whether the code has been assigned. Look the code up in a library catalogue or GS1 database to confirm that.
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