What Is an IBAN?

Who benefits from understanding IBAN structure

People reviewing invoices, payment forms, international account details, and software fields that ask for an IBAN.

IBAN parts at a glance

The main parts of an IBAN

An IBAN is an International Bank Account Number. It uses a standard structure so payment details can be checked before they are used. The exact length and local account structure vary by country.

• Country code: the first two letters, such as DE for Germany or FR for France.
• Check digits: two digits after the country code, used by the IBAN checksum.
• BBAN: the country-specific Basic Bank Account Number part after the first four characters.

Digital format and print format

The digital format removes spaces and is normally used by software systems. The print format groups the same value in blocks of four characters so people can read and compare it more easily.

How an IBAN check helps

A format check can catch many obvious mistakes by checking the country code, expected length, allowed characters, and MOD97-10 checksum.

Why the country rule matters

ISO 13616 gives every IBAN the same opening pattern, but it does not make every national account format identical. Swift's IBAN Registry records a fixed total length and BBAN structure for each participating country. A German IBAN has 22 characters, a French IBAN has 27, and a Dutch IBAN has 18. Letters can be expected in some BBANs and not in others. Checking a value against the rule for its own country avoids treating a legitimate national difference as an error.

• Read the first two letters before deciding which length and character pattern applies.
• Preserve leading zeroes and permitted letters in the country-specific BBAN.
• Use a country page to compare the published structure and an example/test value.

How to review an IBAN from an invoice

Start with the original invoice or payment instruction and isolate the IBAN from nearby text. Print spacing can be removed, but letters and digits must stay in the same order. Compare the compact value with the source, confirm the country-specific length, and then run the checksum check. Keep the beneficiary name, BIC, amount, invoice number, and payment reference in separate fields. This sequence catches data-entry problems without pretending that a browser-local format tool has contacted the account provider.

• Do not append a customer number or payment reference to the IBAN.
• Do not remove letters merely because most of the value is numeric.
• Do not let spreadsheet number formatting strip leading zeroes.
• Confirm changed payment instructions through a trusted contact channel.

What a checksum result actually means

MOD97-10 tests mathematical consistency across the complete IBAN. It is useful for catching many single-character mistakes, missing characters, and transpositions. A passed checksum means the supplied value is structurally consistent with the supported country rule; it does not establish where the value came from. An attacker, outdated invoice, or simple payee mix-up can still provide a checksum-valid account. A failed result also does not reveal the intended replacement, so the safest response is to return to the source rather than guessing.

• Pass: country, length, characters, and checksum matched the local rule.
• Fail: recheck the source value instead of editing digits until it passes.
• Neither result confirms account existence, ownership, or transfer success.

How to use an IBAN reference responsibly

Start with the country code and published length, then compare the country-specific BBAN structure and run a checksum check. Treat those steps as transcription and structure review. Before payment, separately confirm the recipient name, invoice source, amount and payment instructions through a trusted channel because an IBAN can be structurally correct while still being wrong for the intended transfer.

What an IBAN format explanation cannot establish

Format checks only. This guide does not confirm account existence, ownership, bank reachability, or payment success. Read the detailed disclaimer for the full limitation list.

• It does not confirm that the account exists.
• It does not confirm that the account belongs to the intended recipient.
• It does not confirm payment readiness or payment success.
• It does not replace confirmation with a bank, payment provider, invoice issuer, or recipient.

FAQ

Reference data reviewed: 2026-07-17 Next scheduled data review: 2026-10-17 Sources: Swift IBAN Registry Reference data is reviewed periodically. BankCodeKit does not perform live bank, account, sanctions, or payment-network confirmation.