A valid American bank routing transit number is strictly a nine-digit numerical code used by financial institutions to identify specific banks and clearinghouse locations for electronic transfers, direct deposits, and check processing. An eight-digit number does not conform to the standard American routing number format and is likely a misread account number, a postal code, or a specialized identifier used in other international banking systems. Customers can locate their correct nine-digit routing number printed on the bottom left corner of their paper checks or by logging into their secure online banking mobile application.