Your ABA number is a nine-digit code that identifies your specific bank or credit union

An ABA number (also called a routing number) is a nine-digit code assigned by the American Bankers Association to every bank and credit union in the United States. When you set up a checking account, your bank has one ABA number, and that number stays the same for all customers at that branch. It tells other banks and payment systems which institution holds your account.

The ABA number is not unique to you — it's unique to your bank. If you have a checking account at Chase in New York, your ABA number is the same as every other Chase customer in that region. The number that identifies your specific account is your account number, which is different from the ABA number and appears on your checks and statements.

You need the ABA number when you set up direct deposit, arrange wire transfers, or authorize automatic payments. Without it, the sending bank has no way to route money to the correct institution. The ABA number is public information — it appears on the bottom left of every check you write, and you can find it on your bank's website or by calling customer service.

Key Takeaways

  • An ABA number is a nine-digit code that identifies your bank or credit union, not your individual account.
  • The ABA number appears on the bottom left of your checks and is public information you can share without security risk.
  • You need your ABA number and account number together to receive direct deposits, set up automatic payments, or send wire transfers.
  • Different branches of the same bank may have different ABA numbers, so always verify the code for your specific branch location.
  • Your ABA number never changes as long as you keep your account at the same bank, even if you move or change your account type.

Where to find your ABA number on a check

The ABA number is printed on the bottom left of every check you receive from your bank. It's the first set of nine digits, followed by your account number and then the check number. The format is always nine digits with no letters or special characters.

If you don't have checks in front of you, you can find the ABA number on your bank's website, usually in the account settings or help section. Call your bank's customer service line and ask for the routing number for your specific branch — they will give you the nine-digit code immediately. Some banks also print it on statements or in your online banking portal under account details.

How banks use the ABA number to route money

When you receive a direct deposit from your employer or set up an automatic payment to a bill, the sending bank uses your ABA number to identify which institution should receive the money. The ABA number acts like a postal code for banks — it narrows down the destination to your specific financial institution.

The Federal Reserve and other payment networks maintain a database of all ABA numbers and which banks they belong to. When a transfer is initiated, the sending bank looks up your ABA number in that database, confirms it belongs to a real institution, and routes the funds accordingly. If the ABA number is wrong, the transfer will either be rejected before it leaves the sending bank or returned after a few business days.

The difference between ABA number and account number

Your ABA number identifies the bank. Your account number identifies your specific account within that bank. Together, they form the complete routing information needed to send money to you. If you give someone only your ABA number, they cannot deposit money into your account — they also need your account number.

Your account number is typically 8 to 12 digits long and appears on your checks, statements, and in your online banking portal. It's printed on the bottom of your checks after the ABA number. Unlike the ABA number, your account number is unique to you and should be treated with more caution, though it's not considered sensitive information on its own.

What happens if you use the wrong ABA number

If you provide an incorrect ABA number when setting up direct deposit or an automatic payment, the transfer will usually fail before the money leaves the sending institution. The sending bank's system will reject the ABA number because it doesn't match any real bank in the Federal Reserve database, or it will match a different bank than the account number you provided.

In some cases, the transfer may go through to the wrong bank, but it will be caught during the verification process and returned to the sender within one to three business days. The sending bank will then contact you to ask for the correct ABA number. To avoid delays, always double-check the nine-digit code before you submit it, especially for important payments like payroll or mortgage.

ABA numbers for different branch locations

Large banks often have multiple ABA numbers depending on the branch location or the type of account you hold. If you have a checking account at a Chase branch in California, the ABA number may be different from a Chase branch in Texas. Some banks assign one ABA number per state or region, while others use one code for the entire institution.

When you need your ABA number, always specify your branch location to make sure you get the correct code. If you move to a different state or switch to a different branch of the same bank, verify that your ABA number has not changed before you set up new direct deposits or automatic payments. Your bank's website usually lets you filter by branch location to find the correct routing number.

Frequently Asked Questions

Is it safe to share my ABA number?

Yes, your ABA number is public information and sharing it poses no security risk. It's printed on every check you write and is available on your bank's website. However, never share your ABA number along with your account number and PIN to anyone you don't trust, as that combination could allow unauthorized access to your account.

Can I use the same ABA number for multiple accounts at the same bank?

Yes, if you have a checking account and a savings account at the same bank branch, they share the same ABA number. The ABA number identifies the bank, not the individual account. Each account has its own separate account number, so the combination of ABA number plus account number is unique to each account.

What if my bank merged with another bank?

When banks merge, the ABA numbers may change or consolidate. Your bank will notify you if your routing number changes and will provide the new ABA number. Update any automatic payments or direct deposits with the new number to avoid delays. You can confirm the current ABA number by calling your bank or checking their website.

Do credit unions have ABA numbers?

Yes, credit unions have ABA numbers just like banks do. The American Bankers Association assigns routing numbers to all federally insured credit unions and most state-chartered credit unions. You can find your credit union's ABA number the same way you would for a bank — on your checks, your statement, or by calling customer service.

Can I look up someone else's ABA number?

Yes, you can look up any bank's ABA number using the Federal Reserve's routing number database or your bank's website. If you know the bank name and branch location, you can find the nine-digit code. This is public information and is used to verify that a bank exists and is legitimate before you send money to it.