Book & Print Tools › ISBN-13 checker

An ISBN-13 is a 13-digit number that identifies a book edition. The last digit is a check digit calculated from the first twelve, which catches most typing mistakes.

Type or paste an ISBN, with or without hyphens. The tool multiplies the digits alternately by 1 and 3, adds them up, and works out which final digit would make the total a multiple of 10. If that matches the last digit you entered, the number is well formed.

A valid check digit does not prove the ISBN was ever issued to you. Only your national ISBN agency can assign numbers, and this tool does not generate them. Use it to catch typos before the number goes onto your copyright page and barcode.

How to use it

1. Enter the ISBN, hyphens optional.
2. Read the result and the expected check digit.
3. Fix the number if it is not valid before you print it.

Worked example

978-0-306-40615-7 is valid: the check digit 7 is correct.

Questions

Does valid mean registered?

No. It only means the digits are consistent.

Can you generate an ISBN for me?

No. ISBNs are issued by national agencies, and this site does not make them up.

What about ISBN-10?

This tool checks ISBN-13 only, which is the current format.

Why must it start with 978 or 979?

Those are the prefixes reserved for books.

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