ZagTrader

IBAN Checker

Paste an IBAN to check it against the format of its country in the Swift IBAN Registry: the length, the structure of the national account number (BBAN) and the two check digits. A valid IBAN is split into its parts: country, check digits, bank code, branch code where the country defines one, and account number.

The check runs in your browser. Nothing you type is uploaded, stored or logged.

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How an IBAN is built

An IBAN (International Bank Account Number, ISO 13616) starts with the two-letter ISO country code and two check digits, followed by the BBAN: the national account number in a fixed format per country. The longest IBAN allowed by the standard has 34 characters; each country uses one fixed length, from 15 characters in Norway to 33 in Russia.

In electronic messages the IBAN is written without spaces and in capitals. On paper it is printed in groups of four characters, for example GB29 NWBK 6016 1331 9268 19.

PartExample (GB29NWBK60161331926819)What it is
Country codeGBISO 3166 code of the country whose format applies
Check digits29Two digits that protect the whole IBAN against typing errors
Bank codeNWBKNational bank identifier, where the country format has one
Branch code601613Branch or sort code, in countries that define one
Account number31926819The account, including any national check digits

How the check digits are calculated

  • Move the first four characters (country code and check digits) to the end.
  • Replace every letter by two digits: A = 10, B = 11 and so on up to Z = 35.
  • Divide the resulting number by 97. The IBAN is valid when the remainder is 1 (ISO 7064 MOD 97-10).
  • To create the check digits for a new IBAN, do the same with 00 in their place and subtract the remainder from 98.

What a valid result does and does not prove

A valid result means the IBAN is well formed: right length, right structure for its country and correct check digits. It catches nearly every typing error, including two swapped characters.

It does not prove that the account exists, that it is open or that it belongs to the person you are paying. Only the account-holding bank knows that, and a closed or unknown account comes back as a reject or return with a reason code such as AC01 or AC04.

IBAN formats of all 89 countries

Questions

What does this IBAN checker check?
The country code against the IBAN registry, the length for that country, the character types of each position of the BBAN (digits, letters or both), and the MOD 97 check digits.
Is my IBAN sent to a server?
No. The check runs in your browser with JavaScript; the IBAN is not uploaded, stored or logged.
Does a valid IBAN mean the account exists?
No. A valid IBAN is well formed, but only the bank can confirm that the account exists and who holds it. Some countries also have national check digits inside the BBAN, which this tool does not test.
How many countries use the IBAN?
The Swift IBAN Registry (release 99, December 2024) lists 89 countries. Some territories use another country's prefix: French overseas territories use FR, and Jersey, Guernsey and the Isle of Man use GB.
Why does my IBAN fail with the right number of characters?
Either a character is of the wrong type for its position (for example a letter where the country format expects a digit), or a character is mistyped and the check digits no longer match.
Do I need a BIC as well as an IBAN?
Within SEPA an IBAN is enough for euro payments. Cross-border payments outside SEPA usually need the BIC of the beneficiary's bank too; use the BIC checker to check its format.

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Format checks only. A valid result does not confirm that an account, institution or payment exists. Swift is a trademark of S.W.I.F.T. SC; ZagTrader is not affiliated with or endorsed by Swift.