Question 1

What is an IBAN exactly?

Accepted Answer

IBAN stands for International Bank Account Number. It is a standardised format defined by ISO 13616 that uniquely identifies a bank account across countries. Every IBAN starts with a 2-letter country code, then 2 check digits (MOD-97), followed by the country-specific BBAN that contains the bank code and the account number. Length varies from 15 characters (Norway) to 31 (Malta) depending on the country.

Question 2

What does MOD-97 actually do?

Accepted Answer

MOD-97 is a checksum algorithm. The IBAN is rearranged by moving the country code and check digits to the end, every letter is replaced with a 2-digit code (A=10, B=11, … Z=35), and the resulting big number is divided by 97. A valid IBAN always produces a remainder of 1. If anything else comes out, the IBAN has a typo somewhere. The two check digits are computed during account assignment so that the equation works.

Question 3

Why does the validator say my IBAN is correct but my bank rejects it?

Accepted Answer

Format validation only proves that the number could mathematically exist as an account in the country's banking system — it does not prove that the account is currently open at the named bank. An IBAN can pass MOD-97, identify a real bank, and still belong to a closed or never-opened account. Banks check the actual existence in their internal registry, which the validator cannot reach. Use the validator to catch typos before sending; rely on a small test transfer to confirm the account is active.

Question 4

Is the IBAN database complete?

Accepted Answer

We carry the major retail and commercial banks per country (typically the top 10 to 15). When the bank code is not in our database, the rest of the parsing still works and the IBAN is still validated — you just see 'Bank not in our database' instead of the bank name. We expand the database based on user requests; let us know if your bank is missing.

Question 5

Can I check IBANs from outside Europe?

Accepted Answer

Yes for many countries. The validator covers all 27 EU member states plus the UK, Switzerland, Norway, Iceland, Serbia, Liechtenstein, Monaco, San Marino, Andorra, Albania, Georgia and Turkey. Other IBAN-using countries (Saudi Arabia, UAE, Israel, Tunisia, Pakistan and several more) follow the same MOD-97 standard but are not in our country list yet — let us know if you need them and we will add them.

Question 6

Why does my IBAN sometimes start with a letter (NL ABNA, IE BOFI)?

Accepted Answer

Some countries use a 4-letter alphabetic bank code instead of digits. The Netherlands uses ABNA for ABN AMRO, INGB for ING, RABO for Rabobank; Ireland uses BOFI for Bank of Ireland, AIBK for Allied Irish Banks. The format is country-specific and is part of the official IBAN structure published by the European Committee for Banking Standards. The MOD-97 algorithm handles letters by mapping them to numbers (A=10 … Z=35), so the checksum still works.

Question 7

Do you store any of the IBANs I check?

Accepted Answer

No. Validation and generation both run entirely in your browser using JavaScript on the client. There is no API call, no server-side log, no analytics tracker on the form. The IBAN you paste exists only in the browser tab — closing it discards everything.

Question 8

What if I get an IBAN with the wrong country prefix?

Accepted Answer

Each country has a fixed total length and a fixed structure pattern. A 'DE' IBAN has to be exactly 22 characters with 8 digits of bank code and 10 digits of account number; a 'FR' IBAN has to be 27 characters with a specific layout. If the prefix and the rest of the number do not match the country's structure, the validator flags it immediately — this catches a common scam pattern where bad actors swap the country prefix to redirect a transfer.

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