What is the ISBN Validator?
Validate ISBN-10 or ISBN-13 check digits. ITS Research Solution keeps the interactive tool above the explanation so you can calculate first and then review the method used.
Formula or method
ISBN-10 uses mod 11; ISBN-13 uses the alternating 1/3 weighted checksum.
How to use this tool
Enter the requested values using consistent units, run the calculation and review the main result plus any supporting values. Use a hyphenated or plain ISBN; punctuation is removed before validation.
Interpretation and limitations
A valid checksum does not prove that bibliographic metadata are correct. Always check source data, units, rounding and discipline-specific requirements before using a result in assessed, published, regulated or high-stakes work.
Frequently asked questions
How is this result calculated?
ISBN-10 uses mod 11; ISBN-13 uses the alternating 1/3 weighted checksum.
Can I use this result in formal academic or research work?
Use it as a transparent calculation aid, then verify the assumptions, units, rounding and any institution-, journal- or field-specific requirements before formal use.