An ABA number is a nine-digit code that identifies which bank holds your account
Every bank in the United States has its own ABA number (also called a routing number). When you send money to someone else's account—whether by wire transfer, ACH payment, or check—the ABA number tells the payment system which bank to send the money to. Without it, the payment would have nowhere to go.
The number is issued by the American Bankers Association, which is why it's called an ABA number. It's not the same as your account number. Your account number identifies you within your bank; the ABA number identifies the bank itself. Together, they form the complete address for your money.
You'll need your ABA number whenever you set up a payment that leaves your bank—direct deposit from an employer, a wire transfer to pay a contractor, or an automatic bill payment to a utility company. If you're receiving money, the person sending it will ask for your ABA number and account number.
Key Takeaways
- An ABA number is a nine-digit code that identifies your specific bank, not your account within that bank.
- You need your ABA number for wire transfers, ACH payments, direct deposit setup, and any payment that moves money between banks.
- Your ABA number is printed on the bottom left of your checks, or you can call your bank or log into online banking to find it.
- Different branches of the same bank may have different ABA numbers, so confirm you have the right one for your specific branch.
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 any check from your account. You'll see three groups of numbers: the ABA number (nine digits), your account number, and the check number. The ABA number is always the first group on the left.
If you don't have checks or prefer not to look at them, log into your bank's website or mobile app. Most banks display your routing number (another name for ABA number) in the account details section, often under "Account Information" or "Transfer Settings." You can also call your bank's customer service line and ask for your routing number—they'll give it to you immediately.
Some banks also print the routing number on statements or debit cards, though this varies by institution. If you're in a hurry and can't find it online, calling is the fastest option.
How ABA numbers work in different types of payments
When you set up a wire transfer, you provide the recipient's ABA number so the sending bank knows exactly which bank to contact. The two banks communicate directly, and the money typically arrives the same day or within one business day. The ABA number is essential—without it, the wire cannot be routed.
For ACH payments (the system used for direct deposit, bill pay, and peer transfers), the ABA number is also required. ACH is slower than a wire—usually two to three business days—but it's cheaper and works through a clearing house that processes thousands of payments at once. The ABA number tells the clearing house which bank to pull the money from and which bank to send it to.
When you receive a direct deposit from your employer, your employer's payroll system uses your ABA number and account number to deposit your paycheck into your account. If the ABA number is wrong, the deposit goes to the wrong bank and may bounce back to your employer, delaying your pay.
ABA numbers and branch locations
Large banks often have multiple ABA numbers—one for each major branch or processing center. This means two branches of the same bank might have different routing numbers. If you move to a different branch or open an account at a different location, your ABA number may change.
Before you set up a payment, confirm that you're using the ABA number for the correct branch. If you're not sure which branch your account is held at, check your statements or ask your bank. Using the wrong ABA number for your bank won't necessarily cause a payment to fail—it may just route through a different processing center—but it's better to be accurate.
Online banks and credit unions also have ABA numbers. If you bank with an online-only institution, the ABA number still identifies that bank's processing center, even though there's no physical branch to visit.
What happens if you use the wrong ABA number
If you provide an incorrect ABA number when sending money, the payment may still go through if the account number is correct and the receiving bank can identify the account. However, it may take longer to process, or the receiving bank may reject it and send it back to you.
If you receive a payment and give the wrong ABA number, the money could be deposited into the wrong bank entirely. The sender's bank will try to match the account number to the ABA number you provided. If they don't match, the payment bounces back and the sender has to resend it with the correct information.
For wire transfers, an incorrect ABA number is more serious. The sending bank may refuse to process the wire if the routing number doesn't match the account number you provided. Always double-check both numbers before confirming a wire transfer.
ABA numbers and fraud protection
Your ABA number is not secret information—it's printed on your checks and visible to anyone who receives a payment from you. Knowing your ABA number alone does not allow someone to access your account or steal money. They would also need your account number, and even then, they can only pull money out if they have authorization.
However, you should still be cautious about who you give your full banking information to. If someone asks for your ABA number and account number together, make sure you know who they are and why they need it. Legitimate businesses (employers, utilities, loan servicers) will ask for this information when you set up a payment. Scammers sometimes pose as banks or service providers to collect this information.
If you suspect fraud on your account, contact your bank immediately. They can freeze your account, reverse unauthorized transactions, and issue you a new account number if necessary. Your ABA number will stay the same—it identifies the bank, not your specific account.
ABA numbers for international payments
If you're sending money to someone outside the United States, you won't use an ABA number. International wire transfers use a different system called SWIFT (Society for Worldwide Interbank Financial Telecommunication). The receiving bank will have a SWIFT code instead of an ABA number.
If you're receiving money from outside the US, you may need to provide both your ABA number and your bank's SWIFT code. Your bank can give you both pieces of information. Some banks also use an IBAN (International Bank Account Number) for certain countries, which is a longer code that includes the ABA number plus additional country and account information.
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 to complete a payment. The ABA number is nine digits and appears first on a check; your account number is longer and appears in the middle.
Can someone steal money from my account if they know my ABA number?
Not with just the ABA number alone. They would also need your account number, and even then they cannot withdraw money without authorization from your bank. If you're concerned about unauthorized access, contact your bank to review your account activity and set up fraud alerts.
Do I need a different ABA number for each account I have?
No. If you have multiple accounts at the same bank branch, they all share the same ABA number. Your account number is what distinguishes one account from another. If you move to a different branch, your new account may have a different ABA number.
What if I don't have checks—how do I find my routing number?
Log into your bank's website or app and look for account details or transfer settings. You can also call your bank's customer service line and ask for your routing number. They'll provide it immediately over the phone.
Does my ABA number change if I move or change branches?
It may. If you open a new account at a different branch, that account could have a different ABA number. Check with your bank to confirm which routing number applies to your specific account and branch location.