ISBN-13 Validator

Verify ISBN-13 check digit.

Validate ISBN-13 check digit instantly. Free ISBN-13 validator for books.

About ISBN-13

Verify ISBN-13 check digit.

ISBN-13 uses alternating 1/3 weights.

Where it is used

Library cataloging, book sales QA.

How to use the ISBN-13

  1. ISBN-13 — enter the value (e.g. 978-3-16-148410-0).
  2. Calculate — press the Calculate button to see the result instantly above.

Formula

Weights: 1,3,1,3,… sum mod 10; check = (10 - sum) mod 10.

Examples

Example

isbn:978-3-16-148410-0
Result: INVALID ✗

Frequently Asked Questions

ISBN-10 vs ISBN-13?
Different check digit algorithms; ISBN-13 starts with 978 or 979.
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