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IBAN Validator

Check whether an IBAN is written correctly and see what it is made of.

Maintained by BrowserTools · Last updated 2026-09-29

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An IBAN (International Bank Account Number) identifies a bank account in a format that banks in 89 countries and territories agree on. It starts with a two-letter country code and two check digits, followed by the BBAN, the national account number rearranged into a fixed layout that the country registers with SWIFT. Germany uses 22 characters, France 27, Norway only 15 and Saint Lucia 32. Because a single wrong character can send a payment to the wrong place or get it bounced days later, every IBAN carries check digits that catch almost all typing mistakes. This validator runs the same checks a bank's system does before accepting a transfer, and explains in plain words what is wrong when one fails.

Frequently asked questions

How are IBAN check digits calculated?
The method is ISO 7064 MOD 97-10, as used by ISO 13616. Move the first four characters (country code and check digits) to the end, replace every letter with two digits (A is 10, B is 11 and so on up to Z at 35), and read the result as one very large number. For a valid IBAN, that number divided by 97 leaves a remainder of 1. To create check digits, do the same with 00 in their place and subtract the remainder from 98. The number is too big for ordinary floating point, so the tool processes it digit by digit.
Does a valid IBAN mean the account exists?
No. The check only proves the IBAN is well formed: the right length, the right kinds of characters and matching check digits. Anyone can produce a perfectly valid IBAN for an account that was never opened. Invoice fraud often uses real, valid IBANs belonging to the fraudster, so if bank details change unexpectedly, confirm them by phone with a number you already know, and use your bank's payee name check where it is offered.
Can the tool tell me which bank an IBAN belongs to?
No, and it does not try. It shows the bank code and, where the country defines one, the branch code, taken from the positions in the SWIFT registry. Turning that code into a bank name needs each country's own directory of bank codes (for example the Bundesbank list in Germany or sort codes in the UK), which are separate, change often and are not all freely published. Guessing from incomplete data would be worse than not guessing, so look the code up in the official directory of the country concerned.
What kinds of mistakes do the check digits catch?
The mod-97 check detects every single wrong digit and every swap of two neighbouring digits, which are by far the most common typing errors, and it catches the vast majority of other mistakes too: a random error slips through only about once in 97 times. The length and format checks add another layer, catching missing or extra characters and letters where only digits are allowed.
Why is my country not in the list?
Only countries that have registered an IBAN format with SWIFT, the ISO 13616 registration authority, are in the registry. Many large economies, including the United States, Canada, Australia, China, India and Japan, do not use IBANs for domestic accounts and use routing numbers, sort codes or other systems instead, often together with a SWIFT/BIC code for international transfers. Some banks in a few African and Asian countries issue IBAN-like numbers that are not in the registry, and those cannot be validated against the standard.
Why does an IBAN from Guadeloupe or Jersey start with FR or GB?
Some territories do not have their own IBAN entry but are covered by another country's. French overseas departments and collectivities such as Guadeloupe, Martinique, Réunion and New Caledonia use FR, the Åland Islands use FI, and Jersey, Guernsey and the Isle of Man use GB. If you type an IBAN that starts with one of those territory codes, the tool tells you which prefix it should have.
What are the print format and the electronic format?
They are the two ways ISO 13616 lets you write an IBAN. The print format, for paper and screens, splits it into groups of four characters separated by spaces, which makes it easier to read aloud and compare. The electronic format, used in payment files and online banking fields, has no spaces at all and uses uppercase letters. Both contain exactly the same characters, and this tool accepts either one, with or without an IBAN prefix.
Is it safe to paste account numbers here?
Yes. The validator is plain JavaScript running in your browser and makes no network requests with what you type, so IBANs never leave your device. The batch CSV is created locally too. An IBAN on its own is not a secret, since it is printed on every invoice, but keeping lists of customer or employee accounts off third-party servers is still good practice.

About IBAN Validator

Paste an IBAN with or without spaces and the tool checks four things in turn: that the country code is in the SWIFT IBAN Registry, that the length matches that country, that each character of the BBAN is the right kind (digit, letter or either) for its position, and that the ISO 13616 mod-97 check leaves a remainder of 1. When everything is correct it shows the breakdown into country, check digits, bank code and branch code, using the positions each country publishes in the registry, and gives you the IBAN in print format (groups of four) and electronic format (no spaces) ready to copy. The batch tab checks a whole list, one IBAN per line, and exports the results as CSV, which is handy for cleaning a supplier or payroll file before an upload. The check digits tab does the reverse: give it a country and a BBAN and it calculates the two digits that turn it into a complete IBAN.

The country list is the full registry, release 103 from September 2026, including the registry's own example IBAN for each country so you can test with real formats, plus the overseas territories that share the French, Finnish and British codes. Everything happens in your browser: the account numbers you paste are never uploaded, logged or stored. Keep in mind what a validator can and cannot tell you. A valid IBAN is correctly formed, which rules out typos, but it does not prove that the account exists, that it is open or that it belongs to the person named on the invoice. For that, use your bank's payee verification (Confirmation of Payee or Verification of Payee, where available) before sending money.

The IBAN started as a European experiment

The IBAN was designed by the European Committee for Banking Standards in the 1990s, when cross-border payments inside Europe were slow and expensive, partly because every country wrote account numbers differently and errors were only found after a payment failed. The first version of ISO 13616 was published in 1997, and SWIFT became the registration authority that keeps the official list of national formats.

For years the IBAN was optional, and many people first met it on invoices from other countries. The big push came with SEPA, the Single Euro Payments Area: from 2014 the IBAN became mandatory for euro credit transfers and direct debits across the euro area, and it replaced domestic account formats for everyday payments in most of Europe. The standard then spread well beyond Europe, to the Middle East, parts of Africa and Latin America, with Brazil, Saudi Arabia and Pakistan among the adopters.

The choice of 97 is deliberate. It is the largest prime number with two digits, and a prime modulus means that changing any single digit, or swapping two neighbouring digits, always changes the remainder. That is why two small digits can guard an account number up to 34 characters long.

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