Your bank's ABA number is a nine-digit code that identifies which bank holds your account

The ABA number (American Banker Association number) is a routing number specific to your bank's location and branch. It tells the financial system which bank to send money to when you receive a transfer, and which bank to pull money from when you send one. Every bank in the United States has at least one ABA number, and large banks often have multiple numbers for different regions or branches.

You will see the ABA number printed on the bottom left of your checks, alongside your account number. It is also called a routing number or routing transit number (RTN) — these three terms mean the same thing. When you set up direct deposit at work, pay a bill online, or receive a wire transfer, you will need to provide this number so the money reaches the right place.

Key Takeaways

  • Your bank's ABA number is a nine-digit code printed on the bottom left of your checks that identifies your specific bank.
  • The same bank may have different ABA numbers for different regions or branches, so you need the number for your specific location.
  • You will need your ABA number whenever you set up direct deposit, receive a wire transfer, or authorize an electronic payment.
  • You can find your ABA number on a check, by calling your bank's customer service line, or by searching your bank's name on the Federal Reserve's routing number database.

How the ABA number connects to your account number

Your ABA number and your account number work together but serve different purposes. The ABA number identifies which bank you use. Your account number identifies which account at that bank belongs to you. When you provide both together, the financial system knows exactly where to send or pull money.

Think of it this way: the ABA number is like the address of a post office, and your account number is like your mailbox at that post office. The postal worker needs both pieces of information to deliver your mail to the right place. Similarly, a bank processing a transfer needs both numbers to route the money correctly.

Where to find your bank's ABA number

The easiest place to find your ABA number is on a check from your account. Look at the bottom left corner. You will see nine digits printed there — that is your ABA number. The next set of digits to the right is your account number.

If you do not have a check, call your bank's customer service number (usually on the back of your debit card or on your bank's website). A representative can tell you your ABA number in less than a minute. You can also search your bank's name and location on the Federal Reserve's routing number database at frbservices.org, though this requires knowing which branch you use if your bank has multiple locations.

Some banks also display your ABA number in your online banking portal under account details or settings, though not all do. If you are setting up a transfer and the system asks for your routing number, your bank's website usually has a link to find it.

Why banks have multiple ABA numbers

Large banks often maintain separate ABA numbers for different regions, branches, or business lines. This does not mean your account moves between numbers — your account stays with one ABA number. But if you have accounts at two different branches of the same bank, those branches may have different ABA numbers.

When you set up a transfer or direct deposit, you need the ABA number for the specific branch where your account is held, not just any branch of that bank. Using the wrong ABA number will cause the transfer to fail or be delayed. If you are unsure which branch your account belongs to, your bank statement or online banking portal will show it.

What happens if you use the wrong ABA number

If you provide an incorrect ABA number, the transfer will usually be rejected before it leaves your bank. The sending bank's system will not recognize the routing number and will return the money to the sender with an error message. This is a safety feature — it prevents money from going to the wrong institution.

In rare cases, a transfer might go through to a different bank than intended if you transpose digits in a way that creates a valid but incorrect ABA number. If this happens, contact your bank when ready. The sending bank can often recall the transfer within a few hours, but the longer you wait, the harder it becomes to recover the money. Do not assume the receiving bank will send it back on its own.

ABA numbers versus SWIFT codes and IBAN numbers

The ABA number is used only for transfers within the United States. If you are sending or receiving money from outside the US, you will need different codes. International transfers use a SWIFT code (also called a BIC code), which identifies your bank globally. Some countries also use an IBAN (International Bank Account Number), which includes country and account information in a single code.

Your bank can provide both your SWIFT code and IBAN if you need them for international transfers. These codes are longer and more complex than your ABA number, but they serve the same basic purpose: telling the financial system which bank and account to use.

Frequently Asked Questions

Is my ABA number the same as my routing number?

Yes. ABA number, routing number, and routing transit number (RTN) all refer to the same nine-digit code. Banks and financial institutions use these terms interchangeably.

Can someone use my ABA number to access my account?

No. Your ABA number alone cannot be used to withdraw money or access your account. A person would need both your ABA number and your account number, plus authorization from you or your bank. Your ABA number is public information — it appears on every check you write.

Do I need a different ABA number for checking and savings accounts?

No. Both your checking and savings accounts at the same bank branch use the same ABA number. The account number is what distinguishes between them. When you provide both the ABA number and account number, the bank knows which account to use.

What if my bank merged with another bank?

Your ABA number may change after a merger, but your bank will notify you and your account will continue to work during the transition. If you have recurring transfers or direct deposits set up, contact your employer or the other financial institutions involved to update your routing information. Your bank can tell you if your ABA number has changed.

Can I look up someone else's ABA number?

Yes, if you know their bank and branch location. The Federal Reserve's routing number database is public. However, you cannot determine someone's account number from their ABA number alone, so you cannot access their account with this information.