ABA stands for American Bankers Association, and the number is a nine-digit code that identifies which bank holds your account
The ABA routing number is not the same as your account number. It tells the banking system which specific bank or credit union you use. When you send money between banks—through a wire transfer, ACH payment, or direct deposit—the ABA number routes that money to the correct institution. Without it, the payment system would not know where to send your funds.
The American Bankers Association created this numbering system in 1910, long before electronic banking existed. Banks still use the same nine-digit format today. Each bank, and sometimes each branch, has its own ABA number. If you bank at Chase in New York and your friend banks at Chase in California, you may have different ABA numbers.
Key Takeaways
- An ABA routing number is a nine-digit code that identifies your specific bank or credit union in the U.S. banking system.
- You need your ABA number whenever you set up direct deposit, make a wire transfer, or arrange an ACH payment to or from your account.
- Your ABA number is not secret—it appears on the bottom left of your checks and you can find it on your bank's website or by calling customer service.
- The ABA number is different from your account number; together they tell the banking system exactly where your money should go.
Where to find your ABA routing number
The easiest place to find your ABA number is the bottom left corner of any check you have. The first nine digits printed there are your routing number. If you do not have checks, log into your bank's website or mobile app—most banks display the routing number in the account details or settings section.
You can also call your bank's customer service line and ask for your routing number. Have your account number ready when you call. Some banks list routing numbers on their website's FAQ page or in a help section labeled "wire transfer information" or "direct deposit setup."
When you need to provide your ABA number
You will need your ABA number when setting up direct deposit for your paycheck or government payments like tax refunds or Social Security. Employers and government agencies use it to deposit money into your account automatically.
Wire transfers require both your ABA number and your account number. If you are sending money to someone else's bank account, you will need their ABA number and account number. ACH payments—the slower, cheaper version of wire transfers that take one to three business days—also require the ABA number of the receiving bank.
Some bill payment services ask for your ABA number when you set up automatic payments from your account. Mortgage companies, insurance companies, and loan servicers often request it so they can withdraw payments on schedule.
How the ABA number works in the payment system
When you initiate a transfer, the banking system reads your ABA number first. It uses those nine digits to locate your bank in the Federal Reserve's routing directory. Once it finds the right bank, it then uses your account number to find your specific account within that bank.
Think of it like a mailing address: the ABA number is the city and state, and your account number is the street address and apartment number. The system needs both pieces of information to deliver your money to the right place.
The ABA number also helps banks communicate with each other. When money moves between two different banks, the sending bank uses the receiving bank's ABA number to know where to send the funds through the Federal Reserve's network.
ABA numbers for different types of accounts
Most checking and savings accounts at the same bank share the same ABA routing number. However, some large banks have multiple routing numbers depending on which state you opened your account in or which branch you use. Credit unions also have ABA numbers, and they work the same way as bank routing numbers.
If you have accounts at multiple banks, each bank will have a different ABA number. If you move your account from one bank to another, your new bank will give you a new ABA number. Your old ABA number will no longer work for that account.
Online banks and traditional brick-and-mortar banks both use ABA numbers. The format and function are identical—the only difference is how you access your account.
What happens if you use the wrong ABA number
If you provide an incorrect ABA number, the payment may be delayed or sent to the wrong bank. The receiving bank will usually catch the error and send the money back to the sender, but this can take several business days. During that time, you will not have access to the funds.
Some payment systems will reject a transfer immediately if the ABA number does not match the account number you provided. Others will process it and then reverse it once the error is discovered. Either way, you should double-check the ABA number before confirming any transfer.
If a payment goes to the wrong bank by mistake, contact your bank and the receiving bank's customer service. Provide them with the transaction details and ask them to trace the funds. Most banks can recover the money, but it requires documentation and may take one to two weeks.
ABA numbers and security
Your ABA routing number is not sensitive information. It is printed on every check you write and is publicly available on your bank's website. You do not need to keep it secret the way you would keep your account number or PIN secret.
However, you should not share your full banking details—ABA number plus account number—with anyone you do not trust. Someone with both pieces of information can set up automatic withdrawals from your account or initiate transfers. Always verify that you are sending this information to a legitimate business or government agency.
Frequently Asked Questions
Is my ABA number the same as my routing number?
Yes, ABA number and routing number mean the same thing. Banks use both terms interchangeably. It is a nine-digit code that identifies your bank in the U.S. banking system.
Can I use the same ABA number for wire transfers and direct deposit?
Yes. Your ABA routing number works for all types of electronic transfers: wire transfers, ACH payments, direct deposit, and automatic bill payments. You use the same nine-digit code for all of them.
What if my bank has multiple routing numbers?
Some large banks maintain different routing numbers for different states or regions. Check your bank's website or call customer service to confirm which routing number applies to your specific account. Using the wrong one for your branch may delay processing.
Do credit unions have ABA numbers?
Yes. Credit unions use ABA routing numbers just like banks do. The format is identical—nine digits that identify the credit union in the Federal Reserve system. You can find your credit union's routing number the same way you would find a bank's.
Can someone steal money from my account with just my ABA number?
Not with the ABA number alone. A person would need both your ABA routing number and your account number to initiate a transfer or withdrawal. Even then, most banks have fraud detection systems that flag unusual activity. Never share your full account details with anyone unless you initiated the transaction.