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Free online ISBN validator and converter. Validate ISBN-10 and ISBN-13 numbers instantly, convert between formats, calculate check digits, and generate EAN-13 barcodes. Used by publishers, libraries, and bookstores for book identification. Client-side processing โ no data sent to servers.
Check ISBN format, convert between ISBN-10 and ISBN-13, and generate EAN-13 barcodes.
An ISBN (International Standard Book Number) is a unique numeric commercial book identifier assigned to every published edition. Since 2007, all new ISBNs are 13 digits long (ISBN-13). Older books may use the legacy 10-digit format (ISBN-10), which can be converted to ISBN-13.
The ISBN system is defined by ISO 2108 and managed by the International ISBN Agency. It is used worldwide by publishers, libraries, bookstores, and e-commerce platforms for accurate book identification.
Register books with unique identifiers for distribution, tracking, and royalty reporting across markets.
Cataloging and inventory management systems rely on ISBNs for accurate book identification and inter-library loans.
Point-of-sale systems use ISBN barcodes (EAN-13) for inventory tracking and automated checkout.
Online retailers use ISBNs to match product listings, aggregate reviews, and prevent duplicate entries.
Follow these steps to check if an ISBN number is valid using this free ISBN checker:
Type or paste the ISBN-10 or ISBN-13 number. Dashes and spaces are automatically stripped during validation.
The tool checks the format, verifies the check digit using the appropriate algorithm (modulo-10 for ISBN-13, modulo-11 for ISBN-10), and reports validity.
See formatted ISBN, check digit details, and optionally convert between ISBN-10 and ISBN-13. An EAN-13 barcode is automatically generated.
Export the generated EAN-13 barcode as PNG or SVG for use on book covers, packaging, or library labels.
Understanding the differences between the two ISBN formats:
| Feature | ISBN-10 | ISBN-13 |
|---|---|---|
| Length | 10 digits | 13 digits |
| Prefix | None | 978 or 979 |
| Check Digit | Modulo-11 (0-9 or X) | Modulo-10 (0-9 only) |
| Status | Legacy (pre-2007) | Current standard |
| Barcode | Not EAN-compatible | EAN-13 compatible |
| Conversion | Add 978 + recalculate | Only 978-prefix to ISBN-10 |
Multiply each of the first 12 digits by alternating weights of 1 and 3. Sum all products. The check digit is (10 - sum mod 10) mod 10. This makes the total of all 13 weighted digits divisible by 10.
Multiply each of the first 9 digits by its position (1 through 9). Sum all products. The check digit is sum mod 11. If the result is 10, the check digit is represented as X.