IBAN Validator
Check whether an IBAN (International Bank Account Number) is valid — instantly, in your browser, free of charge.
How the check works
Every IBAN ends with a built-in checksum based on the MOD-97 algorithm defined in ISO 7064. To verify it, the first four characters (country code and check digits) are moved to the end of the IBAN, and every letter is replaced with a number (A=10, B=11, ... Z=35).
The resulting long number is then divided by 97. If the remainder is exactly 1, the checksum is correct and the IBAN is structurally valid. This catches almost all typos, such as swapped or mistyped digits — without needing to contact a bank.
Frequently asked questions
- Does a valid IBAN mean the account exists?
- No. This check only verifies the IBAN's checksum and format. It confirms the number is well-formed, not that the account is open or belongs to a specific person.
- Is my IBAN sent to a server?
- No. The check runs entirely in your browser — nothing is transmitted or stored.
- Why does the country code matter?
- The first two letters identify the country that issued the account, which also determines the IBAN's expected length and structure.
- What does the checksum actually protect against?
- It reliably detects common input mistakes like transposed or mistyped digits, so most typos are caught immediately instead of causing a failed transfer.