Validate ISBN-10 and ISBN-13 book numbers.
Validate International Standard Book Numbers (ISBN) in both ISBN-10 and ISBN-13 formats. Perfect for library systems, bookstores, publishing platforms, and book database management. Verifies check digits and format compliance according to ISBN standards.
Validate ISBN-10 and ISBN-13 book numbers.
978-3-16-148410-0
0-306-40615-2
9780306406157
ISBN-10 was the standard until 2007, consisting of 10 digits with the last being a check digit (0-9 or X for 10). The format includes country/language group, publisher code, title number, and check digit. ISBN-10 uses modulus 11 algorithm for validation.
ISBN-13 became mandatory in 2007, using 13 digits starting with 978 or 979 (Bookland EAN prefix). The last digit is a check digit calculated using modulus 10 (similar to barcodes). All new books use ISBN-13, but older books retain ISBN-10.
ISBNs uniquely identify book editions—new formats (hardcover vs paperback) get different ISBNs. The same content in ebook and print has separate numbers. This allows precise tracking in retail, library, and distribution systems worldwide.
Invalid ISBNs cause order fulfillment errors in bookstores and libraries. An incorrect check digit means the wrong book ships, resulting in returns, refunds, and customer frustration. Validating before database entry prevents costly mistakes.
Publishing platforms require valid ISBNs for catalog listings. Amazon, Google Books, and library databases reject invalid numbers, preventing books from appearing in search results. Pre-validation ensures listings go live without delays.
ISBNs enable automated inventory management and sales tracking. Barcode scanners read ISBN-13 as EAN barcodes. Invalid ISBNs break scanning systems, forcing manual entry and slowing operations in warehouses and retail stores.
Strip hyphens and spaces before validation—ISBNs are often formatted with separators for readability (978-0-306-40615-7). Normalize to digits only, keeping 'X' for ISBN-10 check digits. Always convert to uppercase when handling X.
Validate check digits correctly: ISBN-10 uses weighted sum (10×d1 + 9×d2... +1×d10) mod 11 = 0. ISBN-13 uses alternating weights (1,3,1,3...) with sum mod 10 = 0. Implement both algorithms to support legacy and modern ISBNs.
Provide helpful error messages: Instead of 'Invalid ISBN', specify 'Invalid ISBN-10 check digit' or 'ISBN-13 must start with 978 or 979'. This helps users understand whether they have typos or are using the wrong format.
Support conversion between formats: ISBN-10 can convert to ISBN-13 by prefixing 978 and recalculating the check digit. Offer this feature to help users update legacy databases to modern standards.
Libraries use ISBN for cataloging and inter-library loans. MARC records include ISBN fields for cross-referencing. Validating before import prevents duplicate entries from formatting variations (with/without hyphens).
E-commerce platforms match ISBNs to product listings and reviews. Invalid ISBNs create orphaned listings or merge different editions incorrectly. Strict validation maintains database integrity and proper product relationships.
Publishers assign ISBNs from purchased blocks. Validation tools help verify assignments before printing. Catching errors before book production prevents recalls, relabeling, and wasted inventory—expensive mistakes for publishers.
Academic databases and citation managers use ISBNs to identify sources. Invalid ISBNs break automated citation generation and reference verification. Researchers depend on accurate ISBNs for tracking sources across databases.
