Common IBAN Errors
The most frequent mistakes that cause IBAN validation to fail — and how to fix them.
Wrong length
Each country's IBAN has a fixed length. A German IBAN is always 22 characters; a UK IBAN is always 22; a French IBAN is always 27. If yours is shorter or longer, something was cut off or extra characters were added.
Fix: Check the expected length for your country and compare with what you have. Often a digit or group of digits got dropped.
Invalid checksum (mistyped character)
The two check digits (positions 3–4) don't match the rest of the IBAN. This is the most common error and almost always means one character was mistyped. The MOD-97 algorithm catches ~98% of single-digit errors.
Fix: Get the IBAN directly from the bank statement, online banking portal, or ask the recipient to confirm it. Do not try to "guess" or correct check digits manually.
Spaces in the wrong places
IBANs are sometimes written with spaces every 4 characters for readability (e.g. DE89 3704 0044). These spaces are not part of the IBAN and must be stripped before processing. Most validators do this automatically — but some systems don't.
Fix: Remove all spaces and use the 22-character string. Our decoder accepts both formats.
Lowercase letters
IBAN is defined as uppercase only. Some systems or fonts make it easy to confuse uppercase O with 0 (zero), or I (eye) with 1 (one). IBAN fields that use alphabetic characters (type "a") only accept A–Z, not 0–9.
Fix: Convert to uppercase before validating. Our decoder does this automatically.
Wrong country code
The first two letters must be a valid ISO 3166-1 country code for a country that uses IBAN. Not all countries use IBAN — the US, Canada, Australia, and most Asian countries do not. Sending a US account number as if it were an IBAN will always fail.
Fix: Check our list of IBAN countries. If yours isn't there, the recipient may have given you a SWIFT/BIC + account number instead.
Valid IBAN, wrong account
An IBAN can pass all validation checks and still be the wrong account. Checksum validation only confirms the number is correctly structured — it cannot verify that an account with that number exists or belongs to the person you intend to pay.
Always confirm account details directly with your recipient, especially for large transactions. Authorised push payment fraud often uses valid IBANs for fraudulent accounts.