An ABA number is your bank's routing number, and it tells the financial system where to send or pull money
An ABA number is a nine-digit code that identifies your specific bank or credit union. ABA stands for American Bankers Association, the organization that created the system. When you set up a direct deposit, send a wire transfer, or authorize an automatic payment, you give the other party your ABA number so they know which bank to contact and which branch holds your account.
Your bank prints the ABA number on the bottom left of every check you write. It is the first set of nine digits, before your account number. If you do not have checks, you can find it by logging into your online banking portal, calling your bank's customer service line, or visiting your bank's website — most banks list it in the account details section.
The ABA number is not secret and not a security risk on its own. Scammers and fraudsters cannot do much with just the ABA number; they need your full account number as well. However, you should still treat it as part of your banking information and not share it carelessly.
Key Takeaways
- The ABA number is the nine-digit routing code printed on the left side of your checks that identifies which bank holds your account.
- You need your ABA number whenever you set up direct deposit, authorize automatic bill payments, or send a wire transfer.
- The ABA number is the same for all customers at the same bank branch, so it does not uniquely identify you — your account number does that.
- You can find your ABA number on a check, in your online banking account, or by calling your bank's customer service line.
How the ABA number works in a transaction
When you provide your ABA number and account number together, the receiving bank uses the ABA number to route the money to the correct financial institution. Think of it like an address: the ABA number is the city and state, and your account number is the street address. Without the ABA number, the money does not know where to go.
For example, if your employer sets up direct deposit, they enter your ABA number and account number into their payroll system. On payday, their bank contacts your bank using the ABA number, confirms your account exists, and deposits your paycheck. If the ABA number is wrong, the deposit either bounces back to your employer or goes to the wrong bank entirely.
The same process happens with automatic bill payments, wire transfers, and ACH transfers (Automated Clearing House transfers, which are the most common type of electronic money movement in the United States). Each time, the ABA number tells the banking system which institution to contact.
ABA numbers are the same for all customers at your bank
Your ABA number is not unique to you. Every customer at your bank branch has the same ABA number. This is different from your account number, which is unique to your account alone. The combination of ABA number plus account number is what identifies your specific account.
Some banks have multiple ABA numbers if they operate multiple branches or have acquired other banks over time. If you move your account to a different branch or your bank merges with another bank, your ABA number may change. Your bank will notify you if this happens, and you will need to update any automatic payments or direct deposits you have set up.
Where to find your ABA number
The easiest place to find your ABA number is on a check. Look at the bottom left corner of the check. You will see nine digits printed in a special magnetic ink format. Those nine digits are your ABA number. The next set of digits (usually longer) is your account number.
If you do not have checks or cannot find one, log into your online banking account. Most banks display the routing number (which is the same as the ABA number) in the account summary or account details section. You can also call your bank's customer service number, which is usually on the back of your debit card or on your bank's website. A representative can tell you your ABA number in seconds.
Some banks also print the ABA number on statements or deposit slips. If you are unsure, your bank's website almost always has a tool or page that lists routing numbers by branch location.
ABA numbers versus SWIFT codes and other routing identifiers
The ABA number is used only within the United States. If you are receiving money from outside the country or sending money internationally, you will need a SWIFT code instead. A SWIFT code is longer (usually eight to eleven characters) and identifies banks globally.
Some banks provide both an ABA number and a SWIFT code. The ABA number handles domestic transfers, and the SWIFT code handles international ones. If someone outside the United States is sending you money, ask your bank for your SWIFT code, not your ABA number.
Within the United States, you may also hear the term routing number. For most banks, the routing number and the ABA number are the same thing. The terms are used interchangeably.
What happens if you provide the wrong ABA number
If you give someone the wrong ABA number, the money usually does not arrive in your account. Instead, it either bounces back to the sender or goes to the wrong bank. The sender's bank will attempt to contact the bank identified by the incorrect ABA number, and when the account number does not match, the transfer fails.
If money is sent to the wrong bank by mistake, it can take several days or weeks to recover. The sending bank has to trace the transaction, contact the receiving bank, and reverse the transfer. During this time, the money is stuck in limbo. This is why it is important to double-check the ABA number before you authorize a large transfer or set up a new automatic payment.
If you realize you provided the wrong ABA number, contact your bank immediately. They can sometimes stop the transaction before it processes, especially if it has not yet left their system. For automatic payments, you can usually log into your account and edit the routing number before the next scheduled payment date.
Frequently Asked Questions
Is my ABA number the same as my account number?
No. Your ABA number identifies your bank; your account number identifies your specific account within that bank. You need both together to complete a transfer. The ABA number is nine digits and appears on the left side of your checks. Your account number is usually longer and appears in the middle.
Can someone steal money from my account if they have my ABA number?
Not with just the ABA number alone. A thief would also need your full account number and usually some form of authorization from you. However, treat your ABA number as part of your banking information and do not share it with people you do not trust. If you suspect fraud, contact your bank immediately.
Do I need a different ABA number for each account I have at the same bank?
No. If you have a checking account and a savings account at the same bank branch, they share the same ABA number. The account number is what distinguishes one account from the other. You only need to provide the ABA number once per bank.
What if my bank merged with another bank and my ABA number changed?
Your bank will send you a notice explaining the change and providing your new ABA number. You will need to update any automatic bill payments, direct deposits, and standing transfers you have set up. Log into your accounts or call the companies involved and provide the new routing number. Most companies make this change for free.
Can I use my ABA number to receive money from outside the United States?
No. International transfers require a SWIFT code, not an ABA number. Ask your bank for your SWIFT code if you are expecting money from another country. Some banks also require an IBAN (International Bank Account Number) depending on which country the money is coming from.