IBAN Validator - Check 89 Countries

IBAN Validator - Check International Bank Account Numbers

IBAN (International Bank Account Number) is a standardized format for identifying bank accounts internationally. It consists of a country code, check digits, and a bank account number. The check digits use the MOD-97 algorithm (ISO 7064) to detect transcription errors. This validator checks the format, length, and check digits for the 89 countries that issue their own IBAN.

Enter or paste an IBAN to check its structure instantly. The tool reads the country code, verifies the length matches that country's IBAN specification, checks that every position holds the kind of character that country allows there, and runs the MOD-97 checksum. For a well-formed IBAN it names the country, so you can confirm you are looking at the account you meant to.

What this does not tell you. MOD-97 is a checksum. It proves the digits are internally consistent, and nothing more. An IBAN can pass and still carry a bank code that was merged away, closed, or never existed, because the arithmetic never looks the bank up. It also says nothing about whether the account is open or whether it can receive the payment you are about to send. Use this to catch a typo before you pay. If you need to know that a bank code is real and reachable for SEPA, that is a lookup against national bank registers, which no offline checksum can do.

IBAN validation catches the most common payment errors: transposed digits, missing characters, and wrong country formats. The MOD-97 algorithm detects 98% of single-character errors and nearly all transposition errors. Validating IBANs before submitting payments prevents failed transfers, returned transactions, and associated bank fees.

Each country has its own IBAN format and length. Dutch IBANs are 18 characters (NL + 2 check digits + 4-letter bank code + 10-digit account number). German IBANs are 22 characters, UK IBANs are 22 characters, and French IBANs are 27 characters. The tool knows the correct format for each country.

Letters where digits belong. Length and MOD-97 are not the whole story. MOD-97 converts letters into numbers, so it has no opinion about where a letter is allowed to sit. A German IBAN is eighteen digits after the check digits, and a capital O typed in place of a zero can still satisfy the checksum. That is exactly the slip people make when they copy a number off paper or out of a scan: O and 0, I and 1, S and 5. This tool checks each position against the character class that country's specification allows, and tells you which character is wrong rather than only that something is.

Territories that borrow another country's IBAN. An account on Réunion, Martinique or Guadeloupe carries a French IBAN starting with FR, Guernsey, Jersey and the Isle of Man use British IBANs starting with GB, and the Åland Islands use Finnish ones. There is no IBAN that starts with RE or GG. Paste one and the tool says which prefix that territory actually uses, instead of a flat refusal.

The second check digit. Twelve countries put another check digit inside their own part of the IBAN, computed by the bank over the bank code and the account number. Where we can verify one, we do: Belgium, France, Monaco, Spain, Italy, San Marino, Portugal, Slovenia, Poland, Tunisia, Estonia and Hungary. That check is stronger than MOD-97, because MOD-97 can be satisfied by any invented number with the right two digits in front, while this one is computed from the account itself. The Netherlands is deliberately absent: the elfproef was abolished on 1 July 2020 and the old ING giro numbers never satisfied it, so checking it would flag real accounts.

Which bank is it? For Dutch IBANs the tool names the institution behind the four-letter code, including a few that no longer issue accounts but still turn up on old paperwork, such as Postbank. It also says when a code belongs to a payment institution rather than a bank, because money held at a payment institution is not covered by the deposit guarantee scheme. An unrecognised code does not mean the IBAN is wrong: any four letters are structurally valid, listing is voluntary, and new providers appear every year.

For credit card number validation, use our Credit Card Validator.