✅ ISBN Validator — ISBN-10 and ISBN-13
Paste an ISBN with or without hyphens. The tool checks the length and the official check digit, then reprints a compact form.
Input
Result
Summary
Private by design. This tool runs entirely in your browser — nothing you enter or add is uploaded to any server.
How it works
- Paste an ISBN-10 or ISBN-13. Hyphens and spaces are removed.
- Press Validate. ISBN-13 uses a 1-3 alternating sum modulo 10. ISBN-10 uses weights 10 down to 1, with X allowed as the check character.
- Read whether the check digit matches.
Examples
- 9780306406157 is a valid ISBN-13.
- 0-306-40615-2 is a valid ISBN-10.
- 9780306406158 fails the ISBN-13 check digit.
Frequently asked questions
Which standards are checked?
The ISBN-10 weighted checksum and the ISBN-13 GTIN-style check digit. Hyphen group structure is not looked up in the ISBN range registry.
Does X count in ISBN-10?
Yes. A trailing X or x is treated as the check value 10, which is the usual ISBN-10 convention.
Is the number uploaded?
No. The checksum runs in the page.
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