IBAN Validator
Check an IBAN format and check digits.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
IBAN Validator
How to use this tool
- Type or paste an IBAN, with or without spaces.
- Press Generate to run the mod-97 check and the country-length check.
- Use Load sample for a GB IBAN that passes both checks.
Worked example
The sample GB29 NWBK 6016 1331 9268 19 is 22 characters, the expected GB length, and its rearranged numeric form leaves a remainder of 1 when divided by 97, so it passes the mod-97 check.
What this tool does not do / Limits
A passing check means only that the format and check digits are consistent. It does NOT confirm that an account exists, is open, or belongs to anyone, and it does not check the account holder name.
Frequently asked questions
What is the mod-97 check?
The first four characters are moved to the end, letters are replaced by numbers (A = 10 to Z = 35), and the result must leave a remainder of 1 on division by 97.
Can a valid-looking IBAN still fail at a bank?
Yes. A bank can reject a correctly formatted IBAN for a closed, wrong or mismatched account.
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