An ABA number is a nine-digit code that identifies the specific bank or credit union where your account lives
The ABA number, also called a routing number or routing transit number, tells the financial system which institution to send money to when you receive a transfer, direct deposit, or wire. It is not the same as your account number — the ABA identifies the bank itself, while your account number identifies your specific account at that bank.
The name comes from the American Bankers Association, which created the system in 1910. Today, every federally chartered bank, state-chartered bank, and credit union has at least one ABA number. If a bank operates in multiple states or has multiple processing centers, it may have more than one.
Key Takeaways
- An ABA number is nine digits long and identifies your bank or credit union, not your individual account.
- You need your ABA number to set up direct deposits, make wire transfers, and authorize automatic payments from your account.
- Your ABA number appears on the bottom left of your checks, and you can also find it through your bank's website or by calling customer service.
- Different branches of the same bank may have different ABA numbers, so always confirm you have the right one for the branch where your account is held.
Where to find your ABA number
The easiest place to find your ABA number is the bottom left corner of your checks. It is the first set of numbers printed there, before your account number. If you do not have checks or cannot read them clearly, log into your bank's website or mobile app — most banks display the routing number in the account details or settings section.
You can also call your bank's customer service line and ask for your routing number. Have your account number ready when you call. If you bank at a credit union, the process is the same — ask for the routing number or ABA number; both terms mean the same thing.
The Federal Reserve maintains a public database of ABA numbers. You can search by bank name at frbservices.org, though this is usually unnecessary unless you are trying to verify a number someone else gave you.
Why you need it for transfers and direct deposits
When your employer sets up direct deposit, they ask for your ABA number and account number together. The ABA number tells the payroll system which bank to contact; your account number tells that bank which account to deposit into. Without the correct ABA number, the deposit will go to the wrong bank or fail entirely.
The same applies to wire transfers, automatic bill payments, and transfers between your own accounts at different banks. Any time money moves electronically from one financial institution to another, both the sending and receiving banks use ABA numbers to route the transaction correctly.
If you provide the wrong ABA number, the transfer may be rejected before it leaves the sending bank, or it may be sent to a different bank and then returned — a process that can take several business days.
How ABA numbers are structured
All ABA numbers follow the same nine-digit format. The first four digits identify the Federal Reserve district and the bank's location. The next four digits are the bank's unique identifier within that district. The final digit is a check digit — a mathematical verification that the first eight digits are correct.
You do not need to understand this structure to use your ABA number, but it explains why you cannot simply guess or modify a routing number. Each digit has a specific meaning, and changing even one digit will either point to a different bank or fail the check digit validation.
Different ABA numbers for different branches
Large banks with many branches sometimes assign different ABA numbers to different locations or processing centers. This is especially common with banks that have merged or grown through acquisition. Your account may have been opened at one branch but now processes through a different one, which could mean your ABA number changed.
Always use the ABA number for the specific branch where your account is held, not just any branch of the same bank. If you moved your account or your bank reorganized its branches, confirm your current ABA number before setting up direct deposit or making a wire transfer. Your bank's website or a call to customer service will give you the correct one.
What to do if you cannot find your ABA number
If you do not have checks and cannot access your bank's website, call the customer service number on the back of your debit card or on your bank's statement. Have your account number ready. Customer service can provide your ABA number in seconds and can also confirm it is correct for the branch where your account is held.
If you are setting up direct deposit and your employer needs the number immediately, ask your employer if they can look it up themselves — many payroll systems have a bank search tool that finds the correct ABA number when you enter your bank name and state. This is faster than waiting for a call back to customer service.
Frequently Asked Questions
Is my ABA number the same as my account number?
No. Your ABA number identifies your bank; your account number identifies your specific account at that bank. You need both for direct deposits and transfers. The ABA number is nine digits and appears first on your checks; your account number is longer and appears after the ABA number.
Can I use any branch's ABA number if I bank at a large chain?
Not always. Different branches or processing centers may have different ABA numbers. Use the one for the specific branch where your account is held. If you are unsure, ask your bank or check your account details online — using the wrong branch's ABA number can cause transfers to fail or be delayed.
What happens if I give someone the wrong ABA number?
The transfer will likely be rejected before it is sent, or it will be routed to the wrong bank and returned within a few business days. Either way, the money does not reach your account. Always double-check the ABA number before confirming a direct deposit setup or wire transfer.
Do credit unions have ABA numbers?
Yes. Credit unions use ABA numbers just like banks do. The number works the same way — it identifies the credit union and routes transfers correctly. You can find your credit union's ABA number on your checks, through their website, or by calling their member service line.