Files stay on your device
Free. No account needed.ISBN validator
Check ISBN-10 or ISBN-13 check digits and convert valid ISBN-10 values.
Result
Enter your values. Your result will appear here.
How it works
- Inspect the example or enter your own input.
- Check the units and operation, then run the tool.
- Review the result, then copy or download it. Keep a copy of your original data.
Example & practical use
Starting example: ISBN: 978-0-306-40615-7
Limits and help
A valid check digit does not prove a book or publisher exists. Spaces and hyphens are ignored. Runs on your device without uploading input. Maximum 200,000 characters per field; numeric calculations use finite JavaScript numbers unless exact integer/decimal arithmetic is stated.
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Troubleshooting
Try the small example on this page first. If it works, check your input format and size limit. Save any needed input before reloading. You do not need to share a file or password to report an issue.