Wikipedia:Reference desk/Archives/Computing/2021 March 7

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March 7

Checking account number

I have a 10-digit checking account number, formatted like 0123-456789. Does anyone know if that works like a credit card number, i.e. is there a check digit, do the first 4 digits designate the bank, that sort of thing? Do all US checking account numbers have the same format, or anyway are they the same number of digits? I know there is a routing number separate from the account number, so I figure that is what designates the bank. So I'm wondering if the first 4 digits has any special significance. Or what I'm really wondering is: are banks free to generate and issue account numbers any way they please, with some reasonable constraints on the number length etc.? Thanks. 2601:648:8200:970:0:0:0:1A5F (talk) 20:34, 7 March 2021 (UTC)

You could ask your bank. One possibility is that one part is a branch number. As to identifying the bank, see ABA routing transit number. --142.112.149.107 (talk) 23:39, 7 March 2021 (UTC)

Bank account numbers do not have formatting rules like credit card numbers. Every bank has freedom to assign them however they choose. 97.82.165.112 (talk) 00:10, 8 March 2021 (UTC)

But they must put in some checking. About the first four digits, years ago my bank was taken over by a different bank. They added "8500" to the beginning of all account numbers transferred over, so the first four digits may indicate the bank to some extent. Bubba73 ^{You talkin' to me?} 00:43, 8 March 2021 (UTC)

That could have been so that you didn't have a conflict in the database. When I set up checking for myself and my two kids, we got sequential numbers. That tells me that they are just incrementing each new account by 1. The first guy who showed up got 1. The next person got 2. The next person got 3, and so on. When banks merge, they have to ensure that you don't have two people with the same account number. An easy way is to add a number to the beginning of all the account numbers. Then 12300042 won't conflict with the already existing account number 42. 97.82.165.112 (talk) 14:16, 8 March 2021 (UTC)

Thanks all. Anyone know if there would be any technical obstacles (customer acceptance is a different story) to a bank using 16 digit account numbers, like credit card numbers? By obstacles I mean limitations in the national or worldwide check processing networks. 2601:648:8200:970:0:0:0:1A5F (talk) 07:08, 8 March 2021 (UTC)

There is an international standard for that. It's called IBAN. This originated as a European standard, but has been adopted by several non-EU countries too. PiusImpavidus (talk) 09:17, 8 March 2021 (UTC)