What does it mean if the checksum is correct?

Many account numbers contain one special digit whose value depends on other digits in the account number. If there is a typo in the account number, this check digit probably does not fit with the other digits anymore, and we can thereby detect that there is a typo.

 

So, when we say that the checksum is correct, we mean that we calculated the expected check digit and found it to be the same as the actual check digit.

This means that the account number you entered most likely does not contain a typo.

 

(It could, of course, happen, that you enter an account number that contains two typos, one of them in the check digit itself, in a way that the mistyped check digit accidentally fits the mistyped rest of the account number. But this is rather unlikely.)

 

Here is some information on incorrect check sums and their potential causes.