You can find your account number on your account statement or on your check in that same row of numbers where you found your 9-digit ABA Routing/Transit number. Your account number appears on your check to the right of your ABA number.
The ABA routing/Transit number is an identification number assigned to each financial institution and each branch office. Larger institutions may list several routing numbers in the drop-down list on the data entry screen. Match the number, typically nine digits, at the bottom left hand side of your check with the one on the list.