What is an IBAN?

Published October 23, 2026

An IBAN (International Bank Account Number) is a single string of letters and digits that identifies one bank account. It starts with a country code and two check digits, and it is between 15 and 33 characters long. The SWIFT IBAN Registry dated September 17, 2026 lists 89 countries that use it. This guide shows how an IBAN is put together, what each part means in four countries and where to find your own.

The short answer

Before IBANs, every country wrote account numbers its own way. A British account was a sort code and an account number. A German one was a Bankleitzahl and a Kontonummer. An Italian one was ABI, CAB and a conto. A bank abroad had no simple way to tell whether a number was complete, or even which part was which.

The IBAN wraps the national number in a common frame. It puts two letters for the country in front, adds two check digits, and keeps the national details unchanged behind them. A bank anywhere can now read the country, check the length, test the check digits and pass the rest to the right bank. The standard behind it is ISO 13616-1:2020. SWIFT is the registration authority: each country registers its format there, and SWIFT publishes the list as the IBAN Registry.

How an IBAN is built

Every IBAN has the same three layers. Take the registry’s own British example:

Everything after the check digits is called the BBAN, the Basic Bank Account Number. It is simply the national account number in a fixed format. The registry says, for each country, how many characters the BBAN has and which positions are digits or letters. For the UK the pattern is 4 letters, then 6 digits, then 8 digits: 18 characters, plus 4 in front, makes 22.

The check digits are the clever part. They are not chosen by the bank. They are worked out with a division by 97, so that one wrong digit or two swapped neighbouring digits break the sum. Our guide to IBAN check digits shows the calculation step by step.

The same idea in four countries

The frame is always the same. What sits inside it depends on the country. Here are four registry examples side by side:

Germany keeps the old pair of numbers: an 8-digit bank code (Bankleitzahl, BLZ) and a 10-digit account number, filled with zeros on the left. In the example the BLZ 37040044 belongs to Commerzbank in Köln, BIC COBADEFFXXX, according to the Bundesbank bank code file. Our checker shows that name for every German IBAN. More on the German IBAN page.

Italy puts a check letter, the CIN, in front of the national number. In the example the CIN is X. So an Italian IBAN carries two independent checks: the IBAN check digits 60 and the CIN.

France keeps the whole RIB, including its own two-digit key, the clé RIB. In the example the key is 06. The French account part may contain letters, as the M in 0500013M026 shows.

The lengths range from 15 to 33 characters. The full list, with the structure and an official example for each of the 89 countries, is on the IBAN formats by country page.

Print format and electronic format

The same IBAN can be written two ways. In print it is split into groups of four with spaces: GB29 NWBK 6016 1331 9268 19. That is the version for invoices, letters and screens, because people can read and compare it in blocks. In electronic form there are no spaces: GB29NWBK60161331926819. That is the version systems store and send.

Both are the same IBAN. Banking apps usually accept either. Our checker removes spaces, dashes and dots, and turns lower-case letters into capitals, before it tests anything. What you should never do is drop or add a character to make the groups look even. The last group is often shorter than four, as in the German example, which ends in 00.

Where to find your own IBAN

Your bank has already calculated it. Look in these places, in this order:

• Online banking or the banking app. Open the account and look at its details. The IBAN is usually listed next to the account number, often with a copy button.
• A bank statement. Statements usually print the IBAN, often together with the BIC.
• Your bank card. In some countries it is printed on the card. German girocards, for example, carry it.
• Ask the bank. Any branch or helpline can tell you. It is not a secret number.

The IBAN your bank gives you is the binding one. If you only have the national details, the IBAN calculator builds the IBAN from them and works out the check digits. For British accounts you need the sort code, the account number and the 4-letter bank code; the UK IBAN page explains where each part comes from. For German accounts the calculator uses the standard rule, and it gives no IBAN for banks known to convert account numbers by their own rules (Commerzbank, Deutsche Bank, HypoVereinsbank, Oldenburgische Landesbank, the Bundesbank). The full list is given only to registered companies, so compare any German result with your statement.

What an IBAN does not tell you

An IBAN that passes every check is well formed. It has the right country code, the right length, the right characters in the right places and matching check digits. That is all. It does not prove that the account is open, and it says nothing about who holds it. Only the receiving bank knows that.

This matters because the most expensive mistake is not a typing error. A typing error is caught. A correct IBAN for the wrong account is not. That is why banks now compare names. Since 9 October 2025, banks in the euro area must check the payee’s name against the IBAN before you confirm a euro transfer (Verification of Payee, Regulation (EU) 2024/886, Art. 5c). Banks in the other EU countries must do it by 9 July 2027, and the check is free. UK banks run a similar name check called Confirmation of Payee. Read what your bank shows you. If it says the name does not match, stop and ask.

Two EU rules worth knowing

Inside the EU, the IBAN alone is enough for a euro transfer. Banks may no longer ask you for the BIC: since 1 February 2014 for domestic payments and since 1 February 2016 across borders (Regulation (EU) 260/2012, Art. 5). The difference between the two codes is explained in IBAN vs SWIFT/BIC.

The same regulation, in Art. 9, says that a payer or payee may not demand an account in a particular EU country. An employer in one member state cannot refuse to pay salary into your account in another, and a company cannot refuse your direct debit mandate because your IBAN starts with the "wrong" letters. This is often called IBAN discrimination, and it is not allowed.

Is it safe to share?

An IBAN is made to be given out: people need it to pay you. On its own it does not let anyone take money by transfer. The one thing to watch is direct debits you did not agree to. Our guide is it safe to give out your IBAN covers what someone can and cannot do with it.

Check one now

Paste any IBAN below. Each character is tested as you type, against the format of its country. Nothing you type leaves your browser.

Checks format and check digits only. It does not confirm that the account exists or who holds it. Based on the SWIFT IBAN Registry, updated September 17, 2026. · Disclaimer

The IBAN checker on the home page works the same way and shows each part of the IBAN in its own colour.