IBAN validator - check any IBAN online

An IBAN (International Bank Account Number, ISO 13616) has three parts: a two-letter country code, two check digits and the BBAN - the domestic account number, which usually contains a bank code, sometimes a branch code, and the account number itself.

Example: DE89 3704 0044 0532 0130 00 - country DE, check digits 89, bank code (Bankleitzahl) 37040044 and account number 0532013000. A Polish IBAN such as PL61 1090 1014 0000 0712 1981 2874 has 28 characters: PL, check digits 61, an 8-digit sort code (10901014, where 109 identifies the bank) and a 16-digit account number.

1. Move the first four characters (country code and check digits) to the end.
2. Replace letters with numbers: A = 10, B = 11, …, Z = 35.
3. Divide the resulting number by 97. The IBAN is valid when the remainder is 1.

This ISO 7064 MOD 97-10 check catches every single-character error and almost all swaps of adjacent digits, which is why banks reject most mistyped IBANs before a payment leaves. When the checksum fails, the validator also tells you which check digits would fit the rest of the number - but the typo may be anywhere, so compare the whole IBAN with its source.

The validator knows the lengths for more than 75 countries, including all EU and EEA states. The US, Canada and Australia do not use IBANs at all - payments there use routing or BSB numbers and SWIFT/BIC codes.

A passing check means the number is well-formed - nothing more. It does not confirm that the account exists, that it is open, or who owns it. Invoice fraud usually works by swapping in a different but perfectly valid IBAN, so if a supplier suddenly “changes bank details” by email, confirm by phone using a number you already have. In the EU, many banks now show a “verification of payee” name check before you send a transfer - use it alongside this tool.