An ABA transit number is a nine-digit code that identifies which bank holds your account

The ABA transit number (also called a routing number) tells the banking system which specific bank or credit union you use. When money moves between accounts—whether you're setting up direct deposit, sending a wire transfer, or paying a bill through your bank—that nine-digit code is how the system knows where to send it. Without it, a payment can go to the wrong institution or get stuck in processing.

ABA stands for American Bankers Association, the organization that originally assigned these codes in the 1910s. The system is still used today, and every bank and credit union in the United States has at least one ABA number. If your bank has multiple locations or divisions, it may have more than one.

You'll find your ABA number on the bottom left of your checks, in your bank's online banking portal, or by calling the bank directly. It's not secret information—it's printed on every check you write—but you do need the correct one for your specific account location.

Key Takeaways

  • Your ABA transit number is a nine-digit code printed on the bottom left of your checks that identifies your specific bank or credit union.
  • The number is required for direct deposits, wire transfers, ACH payments, and any transaction that moves money between different financial institutions.
  • Each bank branch or division may have its own ABA number, so you need the one for your account location, not just your bank's main number.
  • You can find your ABA number on a check, in your online banking account, or by calling your bank's customer service line.

Where the ABA number appears and how to find it

On a paper check, the ABA number is the first set of nine digits printed along the bottom in magnetic ink. It comes before your account number. If you don't have checks or prefer not to use them, log into your online banking account—most banks display the routing number in the account details or transfer settings section. Some banks label it "routing number," "transit number," or "ABA number" interchangeably.

If you can't find it online, call your bank's customer service number on the back of your debit card or on your bank statement. Have your account number ready, and ask for the ABA transit number for your specific account. The representative will give you the correct nine-digit code in seconds. Do not rely on a general internet search for your bank's routing number—some banks have multiple codes, and using the wrong one delays your payment.

Why banks need it for different types of payments

Direct deposit is the most common use. When your employer or a government agency sends your paycheck, they need your account number and your ABA number to deposit it into the right account at the right bank. Without the correct routing number, the deposit goes nowhere, and you have to contact your employer to resubmit it.

Wire transfers also require an ABA number. If you're sending money to someone at a different bank, you provide both your bank's ABA number (so the sending bank knows where to pull the money from) and the recipient's ABA number (so the receiving bank knows where to deposit it). International wire transfers use a different code called a SWIFT number, but domestic wires use ABA.

ACH payments—the system used for bill pay, peer transfers, and recurring payments—also need the ABA number. When you set up automatic payments to your mortgage lender or utility company, or when you send money through a peer-to-peer app, the ABA number routes the transaction to the correct institution.

The difference between ABA number and account number

Your account number identifies your specific account at your bank. Your ABA number identifies the bank itself. Together, they tell the banking system exactly where your money is. Think of it this way: the ABA number is the bank's address, and your account number is your mailbox at that address.

You need both pieces of information to complete most transfers. If you give someone only your account number without the ABA number, they won't know which bank to send the money to. If you give them only the ABA number without your account number, the money arrives at your bank but not in your account. Both are required for the transaction to work.

What happens if you use the wrong ABA number

If you provide an incorrect ABA number, the payment usually gets rejected before it leaves your account, and you'll see an error message. The sending bank's system checks whether the routing number is valid, and if it doesn't match any active bank, the transaction fails. This is actually a safety feature—it prevents money from going to the wrong institution.

In rare cases, if the ABA number you provide is valid but belongs to a different bank than you intended, the money may be sent to that bank. The receiving bank will eventually notice the account number doesn't exist in their system and return the funds to the sender, but this can take several business days. To avoid this, always double-check the ABA number before you submit a transfer, especially for large amounts or one-time payments.

ABA numbers for different account types at the same bank

Most people have one ABA number for their checking and savings accounts at the same bank branch. However, some large banks assign different routing numbers to different divisions, regions, or account types. For example, a bank's online division might have a different ABA number than its brick-and-mortar branches.

If you have multiple accounts at the same bank, check whether they all use the same ABA number or different ones. The safest approach is to look at the bottom of a check from each account (if you have checks) or to ask your bank directly. Using the wrong routing number for the right bank can still cause delays because the payment may be routed to a different division or account type than you intended.

Frequently Asked Questions

Is my ABA number the same as my bank's main routing number?

Not always. Large banks often have multiple routing numbers for different regions, branches, or account types. Your specific ABA number depends on where your account is held. Check your checks or online banking to confirm you have the correct one for your account, not just your bank's main number.

Can someone steal money from my account if they know my ABA number?

No. Your ABA number alone is not enough to access or withdraw from your account. A person would also need your full account number and usually additional verification. Your ABA number is printed on every check you write, so it's considered public information. Treat your account number as private, but don't worry about the routing number being seen.

Do credit unions have ABA numbers?

Yes. Credit unions use ABA routing numbers just like banks do. You can find your credit union's routing number on your checks, in your online account, or by calling the credit union directly. The process is identical to finding a bank's routing number.

What's the difference between an ABA number and a SWIFT code?

An ABA number (routing number) is used for domestic transfers within the United States. A SWIFT code is used for international wire transfers. If you're sending money to someone in another country, you'll need their bank's SWIFT code instead of an ABA number.

If I move to a different branch of the same bank, does my ABA number change?

It depends on the bank. Some banks use the same routing number across all branches, while others assign different numbers to different locations. Contact your new branch or check your new checks to confirm. If the ABA number changes, update it with your employer or any services that use automatic deposits or payments.