The ABA number is your bank's identifier in the U.S. payment system

The ABA number — also called a routing number or routing transit number — is a nine-digit code that tells the banking system which institution holds your account. When money moves between banks, the ABA number is how the sending bank knows where to send it. Without it, a transfer has nowhere to go.

ABA stands for American Bankers Association, the organization that originally assigned these numbers in the 1910s. The system is still in use today, managed now by Fedwire (the Federal Reserve's wire transfer network) and the clearing houses that process checks and electronic payments.

You will see your ABA number on the bottom left of a paper check, printed as the first set of nine digits. It is also called your bank's routing number because it literally routes your payment to the correct institution.

Key Takeaways

  • Your ABA number identifies which bank holds your account and is required for wire transfers, direct deposits, and ACH payments.
  • The nine-digit code appears on the bottom left of checks and can be found through your bank's website, app, or by calling customer service.
  • Different branches of the same bank may have different ABA numbers, so you need the code for the specific branch where your account is held.
  • The ABA number is public information — sharing it does not expose your account to unauthorized withdrawals because a full account number is also required.

Where the ABA number appears and how to find it

On a paper check, the ABA number is the first nine digits printed at the bottom in the MICR line (the machine-readable strip). It comes before your account number and the check number. If you do not have checks, you can find your ABA number through your bank's website or mobile app — most banks list it under account details or in the section where you set up transfers.

You can also call your bank's customer service line and ask for your routing number. Have your account number ready so they can confirm which branch your account is with, since some large banks assign different ABA numbers to different locations or divisions.

If you need to verify an ABA number belongs to a specific bank, the Federal Reserve maintains a public database you can search online. This is useful if you are receiving instructions from someone else and want to confirm the number is legitimate.

Why you need it for different types of payments

Wire transfers require your ABA number because the sending bank uses it to route money through Fedwire, the Federal Reserve's real-time settlement system. When you send a domestic wire, you provide the recipient's ABA number along with their account number so the money reaches the correct bank and account.

Direct deposits — paychecks, tax refunds, benefits payments — also use your ABA number. Your employer or the government agency sends your ABA number and account number to their bank, which then routes the deposit to your institution. Without the correct ABA number, the deposit may be delayed or sent to the wrong account.

ACH payments (Automated Clearing House transfers) use your ABA number to move money between accounts at different banks. This includes bill payments, peer-to-peer transfers, and recurring subscription charges. The ACH network processes these in batches, typically settling within one to two business days.

ABA numbers versus account numbers — what each one does

Your ABA number identifies the bank. Your account number identifies your specific account within that bank. Together, they form a complete address for your money.

Think of it like mailing a letter: the ABA number is the city and state, and the account number is the street address and apartment number. The post office (the payment network) needs both to deliver the mail to the right place.

This is why sharing your ABA number alone does not put your account at risk. Someone with only your routing number cannot withdraw money or access your account — they would also need your full account number, and even then, most banks require additional verification before processing transfers.

When different branches have different ABA numbers

Large banks often assign different ABA numbers to different branches or divisions. Chase, Bank of America, Wells Fargo, and other national banks may have multiple routing numbers depending on which state or region your account is in.

This matters because if you provide the wrong ABA number — even if it is another branch of your own bank — your payment may be delayed while the system tries to sort it out, or it may fail entirely. Always use the ABA number for the specific branch where your account is held.

Some banks also assign different ABA numbers for different types of accounts or payment methods. For example, a bank might use one routing number for wire transfers and another for ACH payments from the same institution. Your bank's website or customer service can tell you which number to use for your specific transaction.

International transfers and when you need a different code

The ABA number only works for payments within the United States. If you are sending money to or receiving money from outside the U.S., you will need a SWIFT code (also called a BIC code) instead, which identifies your bank in the international payment system.

Some banks provide both an ABA number and a SWIFT code. The SWIFT code is typically longer and includes letters and numbers. If you are making an international transfer, ask your bank for the SWIFT code for your account, not the ABA number.

For transfers between U.S. banks, the ABA number is always what you need. International payments are a different system entirely, and using the wrong code will cause the transfer to fail or be returned.

Frequently Asked Questions

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

No. The ABA number alone is not enough to access your account. Someone would need both your ABA number and your full account number, plus they would still need authorization from you or your bank to process a withdrawal. Most banks require additional verification for transfers, especially from new recipients.

Do I need a different ABA number for each account I have?

Not necessarily. If you have multiple accounts at the same branch, they may share the same ABA number — the account number is what distinguishes them. However, if your accounts are at different branches or different banks, each will have its own ABA number. Check with your bank to be sure.

What happens if I use the wrong ABA number?

The payment may be rejected, delayed, or sent to a different bank. If it goes to the wrong institution, that bank will typically reject it and send it back to the sender. The process can take several business days, so it is worth double-checking the number before you submit a transfer.

Is the ABA number the same as a SWIFT code?

No. The ABA number is for U.S. domestic payments only. A SWIFT code is used for international transfers. If you are sending money outside the United States, you need the SWIFT code, not the ABA number.

Where do I find my ABA number if my bank does not have a website?

Call your bank's customer service line or visit a branch in person. Have your account number ready so they can confirm which branch your account is with, since some banks assign different routing numbers to different locations.