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ISBN and ISSN Validator: Check Checksums
Validate ISBN-10, ISBN-13 and ISSN identifiers with checksum verification. All processing happens in your browser.
HOW TO USE
- 1Type or paste an ISBN-10, ISBN-13 or ISSN on the left.
- 2Validation runs live while you type. No button press needed.
- 3The result on the right shows Valid or Invalid with the identifier type and the normalized value.
- 4Try the sample buttons to see how a correct and an incorrect check digit behave.
EXAMPLE
INPUT
978-0-306-40615-7
OUTPUT
Valid ISBN-13. Normalized 9780306406157.
FAQ
How does the check work?
ISBN-10 uses a mod-11 check digit, while ISBN-13 and ISSN use a mod-10 (EAN) checksum. The last digit is recomputed and compared against the one you entered.
Does it accept hyphens and spaces?
Yes. Hyphens and spaces are stripped during normalization before the checksum runs.
What is the difference between ISBN-10 and ISBN-13?
ISBN-13 is the current standard with 13 digits. ISBN-10 was used until 2007 and has 10 digits, including a possible X check character.
Does it check if the book exists?
No. It validates the number format and check digit only. Use a book database to verify the book itself.