Confidence votes 1.9K. There are two types of numbers on a check, the ABA-designated routing number and the check owner's bank account number. The American Banking Association (ABA) assigned ABA (routing numbers) in 1910, since then each bank is required to have its own ABA number. Originally the first four numbers were supposed to give away the location of the bank, now the numbers are no longer accurate to that purpose.
http://www.answers.com/Q/How_many_numbers_are_in_a_bank_account_number
It depends on the bank. Each bank has a 3 digit institution number, a 5 digit transit/branch number, and a variable account number. For example, BMO and RBC are 7 digits, TD m … ight be 11 or 7, and HSBC is 9 digits. 27 people found this useful.
http://www.answers.com/Q/HOW_MANY_Digits_does_a_us_bank_account_number_have
There is no standard for a bank account number in the US. There is a standard for the routing number, because that's shared between banks; the account number, however, is only of use internally by the bank itself. share | improve this answer.
http://stackoverflow.com/questions/1540285/united-states-banking-institution-account-number-regular-expression
Your routing number is: Your routing number is: Note for California customers: If you opened your account in Southern California, you may see a different routing number on your checks than the number displayed above. You can use either number. Note for California customers: If your account has check-writing capabilities and you opened the account in Southern California, you may see a different routing number on your checks than the number displayed above. 
https://www.wellsfargo.com/help/routing-number/index
IBAN is not used in the US. There is a limit for ACH transactions (4-17 digits), but not all transactions have to be ACH. And yes, the US banking system is antiquated. I'm looking at a DW of 38 different systems at a bank and the length of account varies widely depending on the product.
http://stackoverflow.com/questions/1540285/united-states-banking-institution-account-number-regular-expression
There are two types of numbers on a check, the ABA-designated  routing number and the check owner's bank account number.    The American Banking Association (ABA) assi … gned ABA (routing  numbers) in 1910, since then each bank is required to have its own  ABA number.
http://www.answers.com/Q/HOW_MANY_Digits_does_a_us_bank_account_number_have
Routing number Account number. For your security, we don't display account numbers here. See below for help locating your account number using your account statement or a check. Quick Tip. Online Banking customers, sign on to Wells Fargo Online ® to view your account and routing numbers on your Account Activity page. View your account statement. Your account number is located at the top of your online or paper statement.
https://www.wellsfargo.com/help/routing-number/index
In the US, there are two sets of numbers-the bank routing number (whose length is 9 digits … long and identifies the bank, a state, and potentially a branch) and the account number (whose length varies by bank and uniquely identifies the customer).
http://www.answers.com/Q/HOW_MANY_Digits_does_a_us_bank_account_number_have
The most common length for bank account numbers is 9, 12, or 10 digits. Although they range from 4 to 17 digits long. I have a large database of valid numbers and there's no pattern that I can see to the account number.
http://stackoverflow.com/questions/1540285/united-states-banking-institution-account-number-regular-expression
It depends on the bank. Each bank has a 3 digit institution number, a 5 digit transit/branch number, and a variable account number. For example, BMO and RBC are 7 digits, TD m … ight be 11 or 7, and HSBC is 9 digits. 27 people found this useful.
http://www.answers.com/Q/How_many_numbers_are_in_a_bank_account_number
how many numbers are in a us bank account
There is no standard for a bank account number in the United States. There is no standard for a bank account number in the US.