BSB Number is a six-digit code. The format of the BSB code originally was for the first two digits to indicate the “bank” and the other four digits to specify the “branch” of that financial institution, the first digit of which was the state code indicating the state where the branch was located.

Australian Payments Clearing Association (APCA) is now the regulatory body of cheque clearances and of the BSB codes in Australia. APCA assigns the bank code to a financial institution and the financial institution allocates the other digits to its branches, in line with guidelines set by APCA.