IBAN
What is IBAN?
International Bank Account Number (IBAN) is a standardized code that identifies one specific bank account in a format any bank in a participating country can read. It encodes the domestic account number inside a country prefix and a checksum, so a transfer sent from abroad reaches the right account without manual handling.
The format is defined by ISO 13616, and SWIFT acts as the registration authority that publishes each country's national IBAN layout. As of December 2024 the registry covered 89 countries and territories, concentrated in Europe, the Middle East, and the Caribbean. Banks in the United States, Canada, and Australia don't issue IBANs; those markets route domestic transfers on their own numbering schemes.
Key facts
- Standard: ISO 13616, with SWIFT designated as registration authority under ISO 13616-2:2007
- Maximum length: 34 alphanumeric characters, with the exact length fixed per country
- Segments: two-letter country code, two check digits, then the of up to 30 characters
- Validation: check digits calculated with MOD-97-10, as defined in ISO/IEC 7064:2003
- Coverage: 89 countries and territories in the IBAN registry as of December 2024
- Carried in: payment messages, in a dedicated account identification element
How an IBAN is structured
Every IBAN reads left to right in the same order, whatever its total length.
| Segment | Length | What it holds |
| Country code | 2 letters | ISO 3166-1 alpha-2 code of the country where the account is held |
| Check digits | 2 digits | Checksum over the rest of the IBAN, calculated with MOD-97-10 |
| BBAN | Up to 30 characters | The domestic account number, plus the bank and branch identifiers used locally |
Because the checksum covers every other character, one mistyped digit changes the expected remainder and fails validation before the transfer is ever submitted. That check runs locally, with no call to the receiving bank.
Why it matters
- A valid checksum is not a valid account. An IBAN that passes MOD-97-10 can still point at a closed or non-existent account. The receiving bank returns the funds days later, and return handling fees vary by bank and corridor.
- SEPA routing needs nothing else. For euro credit transfers and direct debits inside , the IBAN alone identifies the destination account, so the is no longer required on the instruction.
- Refusing a foreign IBAN breaches EU rules. Under Regulation (EU) No 260/2012, a business collecting euro payments can't require an account held in its own country. Rejecting a valid IBAN from another member state is known as IBAN discrimination, and payers can report it to their national competent authority.
How it compares
IBAN, BIC, and BBAN appear together in the same payment instruction and are regularly used interchangeably, though each addresses a different thing.
The network carries the messages that move funds between those banks, while the IBAN and BIC only address them.
