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ISO 13616 ยท modulo 97

IBAN checker

Checks the country code, the length and the check digits of an IBAN from 75 countries. It runs in your browser; the IBAN is not sent anywhere.

Enter an IBAN

Spaces and lower-case letters are fine.

What is checked

The country code (ISO 3166), the length fixed for that country, and the two check digits under ISO 7064, modulo 97. For a German IBAN the result also shows the bank code (Bankleitzahl) and the account number it contains.

What a valid IBAN does not tell you

A formally valid IBAN does not confirm that the account exists, that it is open or that it belongs to the named payee. The check digits are pure arithmetic: they catch typos and swapped digits, not fraud. Invoice fraud typically replaces exactly this line with someone else's valid IBAN, so confirm new bank details through a second channel.

How the check digits work

  1. Move the first four characters, country code and check digits, to the end.
  2. Replace every letter with a number: A = 10, B = 11, up to Z = 35.
  3. Divide the resulting number by 97.
  4. If the remainder is 1, the IBAN is formally valid.

Frequently asked questions

Can an IBAN check tell me whether the account exists?

No. The check only shows whether the characters are consistent under ISO 13616. Whether the account exists, and who holds it, only the bank knows.

Why is my IBAN rejected?

Usually because of a typo in the check digits or a wrong length. Spaces and lower-case letters are fine; they are removed or converted before the check.

Is the IBAN sent anywhere?

No. The check runs entirely in your browser; the IBAN you enter does not leave your device and is not stored.