ISBN Validator
Validate ISBN-10 and ISBN-13 book numbers by their checksum.
✓ Valid ISBN-10
How ISBN checksums work
Every ISBN ends in a check digit derived from the others. ISBN-10 weights the digits 10 down to 1 and requires the total to be divisible by 11 (the last digit may be X for 10). ISBN-13 alternates weights of 1 and 3 and requires the total to be divisible by 10. This validation runs entirely in your browser.
More validators: the IBAN validator, the credit card validator, and the email validator.
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