About ISBN/IBAN/Luhn Validator

Validate ISBN, IBAN, and credit card numbers (Luhn check). Part of the DevTools Surf developer suite. Browse more tools in the Fun / Niche collection.

Use Cases

• Validate book ISBNs in library management systems
• Check credit card numbers before submitting payment forms
• Verify IBAN formats for international wire transfers
• Test e-commerce checkout validation logic during development

Tips

• Validate ISBN-10 and ISBN-13 with automatic format detection
• Check credit card numbers with the Luhn algorithm instantly
• Verify IBAN structure including country-specific length rules

Fun Facts

• The Luhn algorithm was patented by IBM scientist Hans Peter Luhn in 1960 (US Patent 2,950,048) and is now used on virtually every credit card worldwide.
• ISBN-13 replaced ISBN-10 on January 1, 2007, because the 10-digit system was running out of available numbers in several language groups.
• IBAN lengths vary by country: Norway uses 15 characters while Malta uses 31, making format validation country-dependent.

FAQ

Which formats does it check?

ISBN-10 and ISBN-13 (book identifiers), IBAN (international bank accounts), and generic Luhn-validated numbers (credit cards, SSNs for some countries).

Does it check if the account exists?

Only the checksum — that the number's structure is internally consistent. For IBAN routing or credit-card authorization, you'd need to call the bank/processor.

What about ISBN-10 to ISBN-13 conversion?

Toggle to convert. ISBN-13 is the current standard (since 2007); ISBN-10 is legacy but still present on older books.

Is Luhn the same as IBAN's check?

Different algorithms. Luhn is a single-digit mod-10 check; IBAN uses a mod-97 check across the whole string. The tool picks the right one for each format.