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Aug 08, 2026
ISBN Validator
Validate ISBN-10 and ISBN-13 book identifiers with checksum verification and format conversion.
ISBN Validator
Enter an ISBN (with or without hyphens). ISBN-10 and ISBN-13 are both supported.
Type
-
Check Digit
-
Formatted
-
ISBN-13
-
How to Use
- Enter an ISBN — Type or paste an ISBN-10 or ISBN-13. Hyphens are handled automatically.
- Instant validation — The ISBN is validated in real-time using the appropriate checksum algorithm.
- View details — See the format type, check digit, and formatted version.
- Convert — ISBN-10 is automatically converted to ISBN-13 (prefix 978).
What Is an ISBN?
The International Standard Book Number (ISBN) is a unique numeric identifier for books. ISBNs are either 10 digits (ISBN-10) or 13 digits (ISBN-13) long. ISBN-13 has been required since 2007 and includes the EAN prefix (978 or 979).
An ISBN-13 breaks down as: Prefix (3) + Registration Group (1-5) + Registrant (2-7) + Publication (1-6) + Check Digit (1)
- Prefix — 978 or 979 (Bookland EAN prefix)
- Registration group — Country or language area (e.g., 0 = English, 2 = French)
- Registrant — Specific publisher
- Publication — Specific edition of a book
- Check digit — Validates the entire ISBN
Registration Group Ranges
| Range | Group |
|---|---|
| 0 | English (US, UK, Australia, etc.) |
| 1 | English (South Africa, Zimbabwe) |
| 2 | French |
| 3 | German |
| 4 | Japanese |
| 5 | Russian |
| 6 | Chinese |
| 7 | Spanish |
| 80-94 | Various countries |
| 978-999 | Various countries |
Frequently Asked Questions
What is the difference between ISBN-10 and ISBN-13?
ISBN-10 uses a 10-digit format with a mod-11 checksum (last digit can be X), while ISBN-13 uses a 13-digit format with a mod-10 checksum. ISBN-13 became the standard in 2007.
Can I convert ISBN-10 to ISBN-13?
Yes, simply add the prefix "978" and recalculate the check digit. Not all ISBN-10s can be converted — those starting with a 979 prefix in ISBN-13 have no ISBN-10 equivalent.
What does the check digit validate?
The check digit validates the entire ISBN. For ISBN-10, the weighted sum (weights 10,9,8,...,2) must be divisible by 11. For ISBN-13, the weighted sum (alternating 1,3,1,3,...) must be divisible by 10.
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