What does a wrong checksum mean?
If the IBAN calculator tells you that the account number you entered contains an incorrect checksum, there are several possibilities:
- Maybe you have a typo in the bank code or account number you entered. Please check them both. If there is a typo in one of these numbers, of course the resulting IBAN will be incorrect as well.
- Is this maybe a special account, for example one for collecting donations for a large organisation, or the account of a very special and influential person (founder of the bank, important politician etc.)? Sometimes "pretty" account numbers like e. g. account no. 1 are used because of their beauty even if they don't fit into the checksum scheme. Therefore, it is possible that the account number is correct although it contains an incorrect checksum.
- Maybe the account was opened at a bank that later got bought by another bank. Sometimes this has the effect that while the account number stays the same, the checksum method changes.
- Maybe you discovered an error in our checksum checking software. This is likely if you are certain you entered a correct account that belongs to a normal person, so that the second possibility does not apply. In this case, we would be very grateful to be notified by e-mail!
Even if it encounters an incorrect checksum, the IBAN calculator will calculate an IBAN, especially because of the second possibility above. But you should then check whether you really entered the correct account to avoid ending up with an incorrect IBAN.
Checking an account number and calculating an IBAN for it are two independent steps. So, if we raise a false alarm, you can still get a correct IBAN.
If you think you encountered a software bug, please let us know:
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