ISBN Validator
Validate ISBN-10 and ISBN-13 syntax and check digits before cataloguing or data import.
Accuracy note: Review the generated result against the rules, policies and source data that apply to your organization. The tool explains its assumptions so you can identify where professional judgment is still required.
How this result is calculated and when to review it
Method: Normalizes the identifier, applies the official ISBN-10 or ISBN-13 weighted check-digit formula, and compares the calculated check digit with the supplied value.
Result type: Rule-based / deterministic.
Good practice: keep one known-good example, test small batches first, and document any local conventions that affect the result.
Worked example
Try 9780306406157, a well-formed ISBN-13 example, then intentionally change the last digit to confirm the validator catches the failed check digit.
Enter the example above in the tool, run it and compare the result with the expected outcome. Where default values are provided, Reset restores those values.
Check an ISBN before cataloguing
Paste an ISBN-10 or ISBN-13 into the field and choose Validate ISBN. Hyphens and spaces may be included. The result shows the normalized number, whether its check digit is valid and the expected complete value. Use Copy result to retain the result, or Reset to restore the sample.
Examples to try
9780306406157: valid ISBN-13 check digit.9780306406158: invalid check digit; the expected final digit is 7.080442957X: valid ISBN-10; X represents the check-digit value ten.0-8044-2957-X: the same ISBN-10 with hyphens.
What the check proves
The validator checks number length and the mathematical check digit. A passing result does not prove that an ISBN was assigned by an ISBN agency, belongs to the edition in hand or matches the title, author and publisher in your catalogue. Verify those details against the publication and reliable bibliographic records.
ISBN-10 uses a weighted modulus-11 check; ISBN-13 uses alternating weights of 1 and 3 with a modulus-10 check. For assignment and cataloguing rules, consult the International ISBN Agency manual linked above.
Privacy and next steps
This ISBN check runs in your browser. It does not need patron records or account credentials. After checking the identifier, review the corresponding MARC 020 field and bibliographic identity before importing the record. Report an unexpected result through Contact VWS Online, including a non-confidential example.
Continue the workflow
- 1ISBN ValidatorComplete and review this result first.
- 2MARC21 Record Builderbuild a structured MARC21 bibliographic record and export it in librarian-friendly formats
- 3Excel to MARC Converter for Koha Librariesconvert spreadsheet cataloguing data into MARC21 records for Koha and other MARC-based systems
- 4MARC21 Validatorvalidate MARC21 record structure, fields, indicators, subfields and optional Koha 952 item data before import or migration