IBAN Validator and Parser

An IBAN (International Bank Account Number) identifies a bank account for cross-border transfers in Europe, the Middle East and beyond. One wrong character can send a payment back days later with a fee. This validator checks the country code, the exact length for that country, the character pattern of the national part and the two check digits. It splits out the bank code, branch or sort code and account number where the format defines them, and prints the IBAN in the usual groups of four. Paste a whole list to check many at once.

How to use this tool

1. Paste an IBAN, with or without spaces; lower case is fine.
2. Read the verdict and, if it fails, the reason: unknown country, wrong length, wrong format or a check-digit mismatch.
3. Copy the print format (groups of four) or the electronic format (no spaces).
4. For a list, paste one IBAN per line and read the table.

Formula

Move the first four characters to the end, replace each letter by 10–35 (A = 10 … Z = 35), and the resulting number mod 97 must be 1 (ISO 7064 MOD 97-10).

Lengths and formats come from the SWIFT IBAN Registry as checked in November 2026: 89 countries and territories, including Honduras and Yemen. Places covered by another country's format use that country's code: the Åland Islands use FI, French overseas territories FR, and Jersey, Guernsey and the Isle of Man GB. The national part (BBAN) has a fixed pattern of digits, capital letters and alphanumerics per country. Check digits are found as 98 − (BBAN + country code + "00" mod 97). The tool shows the digits that would fit when they fail, but a mismatch almost always means a different character is wrong. National check digits inside the BBAN (French RIB key, Italian CIN, Spanish DC) are shown but not recalculated.

Example

For GB82 WEST 1234 5698 7654 32: country United Kingdom, 22 characters as required, bank code WEST, sort code 12-34-56, account 98765432. Rearranged, WEST12345698765432GB82 becomes 3214282912345698765432161182, and that number mod 97 = 1, so the IBAN is valid. Change the last digit to 3 and the remainder is no longer 1, so the IBAN fails.