Your bank's ABA number is a nine-digit code that identifies which bank you use

The ABA number (also called a routing number) is a unique identifier assigned to your bank by the American Bankers Association. It tells the financial system which bank holds your account. When money moves between banks—whether you're setting up direct deposit, sending a wire transfer, or paying a bill through another bank's system—that nine-digit code is how the sending bank knows exactly where to send the funds.

Every bank in the United States has at least one ABA number. Large banks with multiple branches may have different ABA numbers for different regions or processing centers. The number itself is not secret; it's printed on the bottom left of your checks, and you can find it on your bank's website or by calling customer service.

Key Takeaways

  • Your bank's ABA number is a nine-digit code printed on the bottom left of your checks and used to route money between banks.
  • You need the ABA number when setting up direct deposit, making wire transfers, or arranging automatic payments from another institution.
  • The ABA number is not confidential; it's public information that appears on checks and bank websites.
  • Different branches of the same bank may have different ABA numbers, so confirm you have the correct one for your specific branch.

Where to find your bank's ABA number

The easiest place to locate your ABA number is the bottom left corner of any check from your account. The nine digits appear before your account number. If you don't have checks or prefer not to use them, you can find the number on your bank's website—usually in the customer service or account information section—or by calling your bank's customer service line and asking for the routing number for your branch.

When you call, specify your branch location. Some large banks route transactions through different processing centers depending on where your account was opened or which branch you use. Giving the wrong ABA number won't send your money to the wrong person, but it may cause the transfer to be rejected or delayed while the system sorts out the mismatch.

When you actually need to provide the ABA number

You'll need your bank's ABA number in specific situations where money is moving from one financial institution to another. The most common scenario is setting up direct deposit with an employer or government agency—they use the ABA number plus your account number to deposit your paycheck directly into your account. You also need it when arranging automatic bill payments through a biller's website (not your bank's bill pay system), transferring money between your accounts at different banks, or sending a wire transfer.

You do not need the ABA number for transactions within your own bank, such as transferring money between your checking and savings accounts at the same institution. You also don't need it when paying bills through your bank's own bill pay service, because your bank already knows its own routing information.

The difference between ABA number and account number

The ABA number and your account number are two separate pieces of information that work together. The ABA number identifies your bank; your account number identifies your specific account within that bank. On a check, the ABA number appears first (bottom left), followed by your account number (bottom center). Both are needed for most transfers, but they serve different purposes.

Think of it this way: the ABA number is like the address of the bank building, and your account number is like your mailbox inside that building. The sending bank needs both to know where to send the money and which account to put it in.

What happens if you provide the wrong ABA number

If you give an incorrect ABA number, the transfer usually won't go through at all. The sending bank's system will reject it because the routing information doesn't match any valid bank. You'll typically get a notification that the transfer failed, and you can resubmit it with the correct number.

In rare cases, if the wrong ABA number happens to belong to a real bank, the money might be sent to that bank instead of yours. However, the account number won't match anything in that bank's system, so the funds will be held or returned to the sender. This is why banks have error-correction processes: the receiving bank will notice the mismatch and either return the money or hold it while they investigate. The process can take several business days, but the money doesn't disappear.

ABA numbers for wire transfers and ACH transfers

Both wire transfers and ACH transfers (Automated Clearing House transfers) use the ABA number, but the process works slightly differently. For a wire transfer, you provide the ABA number along with the receiving account number and the recipient's name. Wire transfers are faster—usually completed the same business day—and are typically used for larger amounts or time-sensitive payments.

ACH transfers also use the ABA number but move more slowly, usually taking one to three business days. ACH is the system behind direct deposit, automatic bill payments, and most person-to-person transfers through services like Venmo or PayPal (though those apps may not ask you for the ABA number directly). Both systems need the correct routing information to work, so the ABA number matters equally for each.

Frequently Asked Questions

Is the ABA number the same as the SWIFT code?

No. The ABA number (routing number) is used for domestic transfers within the United States. The SWIFT code is used for international transfers and identifies banks globally. If you're sending money to someone outside the U.S., you'll need their bank's SWIFT code, not the ABA number.

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

Having only the ABA number is not enough to access or drain your account. A person would also need your account number and typically some form of authorization or verification. The ABA number is public information printed on checks, so it's not considered confidential. However, you should still protect your full account number and never share it with people you don't trust.

Do credit unions have ABA numbers?

Yes. Credit unions are assigned routing numbers (ABA numbers) just like banks. If you have an account at a credit union, you can find the routing number on your checks or by contacting the credit union directly. The process for using it in transfers is the same as with a bank.

What if my bank merged with another bank?

After a merger, your bank may keep the same ABA number or be assigned a new one. Your bank will notify you of any change and update the information on your checks. If you have automatic payments or direct deposits set up, contact your employer or billers to confirm they have the current routing number. Using an old ABA number after a merger may cause transfers to fail.