IBAN Validator
Validate international bank account numbers with MOD-97 check and format parsing
Enter an IBAN above to validate its format and check digits. All validation runs locally in your browser — no data is sent to any server.
IBAN (International Bank Account Number) is a standardized format for identifying bank accounts across national borders. This tool validates the structure, check digits, and country-specific format of any IBAN — entirely in your browser.
How IBAN Validation Works
IBAN validation follows ISO 13616 and uses the MOD-97 algorithm (ISO 7064):
- Move the first 4 characters to the end
- Convert letters to numbers (A=10, B=11, …, Z=35)
- Compute the remainder when divided by 97
- If the remainder is 1, the IBAN is valid
This catches all single-digit errors and most transposition errors — the most common mistakes when typing or copying bank numbers.
Country-Specific Formats
Each country defines its own IBAN length and BBAN structure:
- Germany (DE): 22 characters — 8-digit bank code + 10-digit account
- United Kingdom (GB): 22 characters — 4-letter bank code + 6-digit sort code + 8-digit account
- France (FR): 27 characters — 5-digit bank code + 5-digit branch + 11-digit account + 2-digit key
- Netherlands (NL): 18 characters — 4-letter bank code + 10-digit account
Privacy
IBAN numbers are sensitive financial data. Online validators that send your IBAN to a server create unnecessary exposure. This tool validates entirely in your browser — no network requests, no server storage.