An ABA number is a nine-digit code that identifies the specific bank or credit union where your account lives
The ABA number (also called a routing number) tells the financial system which institution to send money to when you receive a transfer. It is not your account number, your card number, or your Social Security number — it is the bank's identifier. Every federally chartered bank, state-chartered bank, and credit union in the United States has one.
You need this number when someone sends you money via ACH transfer (the system that moves money between accounts), wire transfer, or direct deposit. The ABA number ensures the money lands at your bank, not someone else's. Without it, the transfer cannot be routed correctly.
The number is public information. You can share it freely without security risk, because a transfer also requires your account number to actually move money into your specific account. The ABA number alone cannot access your funds.
Key Takeaways
- Your ABA number is a nine-digit code that identifies your bank or credit union; it is different from your account number and is safe to share.
- You need your ABA number whenever someone sends you money via ACH transfer, wire transfer, or sets up direct deposit to your account.
- You can find your ABA number on the bottom left of your checks, in your online banking portal, or by calling your bank's customer service line.
- The ABA number routes money to the correct bank; your account number routes it to your specific account within that bank.
Where to find your ABA number
The easiest place to look is the bottom left corner of any check you have. The first set of nine digits printed there is your ABA number. If you do not have checks or prefer not to look them up, log into your online banking account — most banks display the routing number in the account details or transfer settings section.
You can also call your bank's customer service number (usually on the back of your debit card) and ask for your routing number. Have your account number ready when you call. Some banks also print the ABA number on statements or in account documentation you received when you opened the account.
ABA numbers versus account numbers: what each one does
The ABA number identifies the bank itself — think of it as the bank's address in the financial system. The account number identifies your specific account within that bank. Together, they tell the payment system exactly where your money should go.
When you give someone your information for a transfer, you provide both numbers. The ABA number routes the payment to your bank; the account number routes it to your account. If you give the correct ABA number but the wrong account number, the money will arrive at your bank but go into someone else's account. If you give the wrong ABA number, the payment may bounce back or land at the wrong bank entirely.
When you need your ABA number
You need your ABA number whenever you set up a transfer into your account. Common situations include direct deposit from an employer, ACH transfers from another person or business, wire transfers, and bill payments where you authorize a company to pull money from your account. Some employers ask for it when you start a job; some landlords ask for it when you set up automatic rent payments.
You do not need your ABA number to send money out of your account (though you may need the recipient's ABA number). You do not need it to use your debit card, pay with a mobile wallet, or make purchases online. It is only required for transfers between bank accounts.
Why the ABA number system exists
The ABA number was created by the American Bankers Association in 1910 to sort checks by hand before electronic banking existed. The system stuck around because it works: it is a standardized way to identify thousands of financial institutions across the country without confusion or delay.
Today, the Federal Reserve and the ACH network still use ABA numbers to route payments. When you set up direct deposit or authorize an ACH transfer, the payment processor uses your ABA number to find your bank in its database, then uses your account number to find your account within that bank. The system processes millions of transactions daily this way.
What happens if you give the wrong ABA number
If you provide an incorrect ABA number, the payment may be rejected outright — the system will not find a matching bank and the transfer will fail. The money stays with the sender, and you will be notified that the transfer did not go through. This is actually the safest outcome because the money does not disappear.
In rare cases, if the wrong ABA number happens to belong to a real bank, the payment might be sent there instead of to your bank. This is why it is important to double-check the number before confirming a large transfer. If this happens, contact your bank immediately; they can often trace the payment and request it be rerouted to the correct institution, though the process can take several business days.
ABA numbers for different types of accounts
Your ABA number is the same whether you have a checking account, savings account, or money market account at the same bank. Some banks use different ABA numbers for different branches or different states, so if you have accounts at multiple branches, verify which number applies to each account. Credit unions also have ABA numbers, and the process is identical — you can find it on checks or by calling the credit union.
If you move your account to a different bank, your new bank will have a different ABA number. You will need to update direct deposit information with your employer and update any automatic bill payments you have set up. The old ABA number will no longer route payments to you.
Frequently Asked Questions
Is it safe to give someone my ABA number?
Yes. The ABA number is public information and cannot be used to access your account or withdraw money on its own. A transfer also requires your account number, and even with both numbers, the sender cannot take money from your account — they can only send money to it. Never share your account number or PIN, but the ABA number is safe to share.
Can I have more than one ABA number?
If all your accounts are at the same bank and branch, they share one ABA number. If you have accounts at different banks or different branches of the same bank in different states, each may have a different ABA number. Check your statements or online banking to confirm which number applies to each account.
What if I cannot find my ABA number?
Call your bank or credit union's customer service line — they can tell you your routing number in under a minute. Have your account number ready. You can also visit the Federal Reserve's routing number search tool online, though calling is usually faster.
Do I need my ABA number to receive a wire transfer?
Yes. Wire transfers require your ABA number, account number, and account holder name. Some wire transfers also ask for a SWIFT code if the money is coming from outside the United States. Provide all the information the sender requests to avoid delays.