A bank transit 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 — tells the financial system which institution to send money to or pull money from. When you set up direct deposit, pay a bill by check, or move money between banks, that nine-digit code is what makes sure the transaction reaches the right place. Without it, the money doesn't know where to go.
The first four digits identify the Federal Reserve district and the bank's location. The next four digits are the bank's own identifier within that district. The last digit is a check digit — a mathematical safeguard that catches typos before the transaction processes. If you enter even one digit wrong, the payment may bounce or go to the wrong account.
Every bank and credit union has at least one ABA number, and large institutions may have multiple — one for each branch or processing center. The number stays the same whether you're moving $10 or $10,000, and it doesn't change when you open a new account at the same bank.
Key Takeaways
- Your bank's ABA number is a nine-digit code printed on the bottom left of your checks, and it identifies which bank holds your account.
- The ABA number is required for direct deposit, wire transfers, ACH payments, and any transaction that moves money between banks.
- You can find your ABA number on your checks, your bank's website, by calling the bank, or through the Federal Reserve's routing number search tool.
- Entering the wrong ABA number will cause a payment to fail or go to the wrong account, so double-check before confirming any transaction.
Where to find your bank's ABA number
The easiest place to look is the bottom left corner of any check you have from that bank. The first nine digits printed there are the ABA number. If you don't have checks, log into your online banking account — most banks display the routing number in the account details or transfer settings section.
You can also call your bank's customer service line and ask for the routing number. Have your account number ready, because some banks have different routing numbers for different types of transactions (checking versus savings, for example, though this is rare).
If you need to find the ABA number for a bank you don't use, the Federal Reserve maintains a searchable database at frbservices.org. Enter the bank name and state, and the system will return all routing numbers associated with that institution. This is useful if you're receiving a wire transfer and need to give someone else your bank's information.
Why refunds and payments require an ABA number
Tax refunds, insurance payouts, stimulus payments, and business reimbursements all use the ABA number to deposit money directly into your account. The IRS, your state tax agency, or the paying organization needs three pieces of information: your bank name, your account number, and your ABA number. Together, these three items create a complete address for your money.
Direct deposit is faster and more secure than mailed checks. A check can be lost, stolen, or delayed in the mail for weeks. A direct deposit using the correct ABA number typically arrives within one to three business days. If you're waiting for a refund and the organization asks for banking details, providing the ABA number is what makes the deposit possible.
The same applies to ACH payments — the system that moves money between banks for bill pay, payroll, and peer-to-peer transfers. Every ACH transaction requires the receiving bank's ABA number to route the payment correctly.
The difference between ABA number and account number
These are two separate pieces of information, and you need both. Your ABA number identifies the bank. Your account number identifies your specific account within that bank. Think of it like an address: the ABA number is the city and bank branch, and the account number is your specific mailbox.
Your account number is usually 8 to 12 digits long and appears on your checks, statements, and online banking portal. It's unique to you and changes only if you close the account and open a new one. The ABA number, by contrast, is the same for everyone with an account at that bank (or at that specific branch, in rare cases).
When you give someone your banking information for a refund or payment, you'll provide both numbers. Some forms ask for them separately; others ask for the "routing and account number" together. Make sure you're putting each number in the correct field.
What happens if you enter the wrong ABA number
If you enter a digit incorrectly, one of two things usually happens. The check digit at the end of the ABA number catches the error, and the transaction is rejected before it processes. You'll get a notification that the routing number is invalid, and you can correct it and try again.
If the error slips through and the money goes to the wrong bank, the receiving bank will typically reject the deposit and send it back to the sender. This takes several business days. You'll then need to resubmit the transaction with the correct ABA number. During this time, you won't have access to the money, and the refund timeline will be delayed.
In rare cases, money sent to the wrong account at the wrong bank can be harder to recover. This is why double-checking the ABA number before confirming any transaction is worth the extra 30 seconds. If you're unsure, call your bank and read the number back to them to confirm.
ABA numbers for wire transfers and international payments
Wire transfers use the ABA number the same way ACH payments do — to route the money to the correct bank. However, wire transfers are faster (often same-day) and more expensive, and they're harder to reverse if something goes wrong. This makes accuracy even more critical.
If you're receiving an international wire transfer, you may also need a SWIFT code in addition to the ABA number. The SWIFT code is an eight-character identifier used by banks outside the United States. Your bank can provide both numbers if you need them.
For domestic wire transfers within the U.S., the ABA number is sufficient. The sending bank uses it to identify your bank, and the receiving bank uses it to confirm the deposit is going to the right institution.
Frequently Asked Questions
Is the ABA number the same as the routing number?
Yes. ABA number and routing number are the same thing. ABA stands for American Bankers Association, the organization that created the system. You'll see both terms used interchangeably by banks and government agencies.
Can I use the same ABA number for checking and savings accounts at the same bank?
Usually yes. Most banks use one ABA number for all account types at a given branch. However, some large banks have different routing numbers for different services or regions. Check your statements or call the bank to confirm if you have both checking and savings accounts.
Do I need an ABA number to receive a check from someone?
No. Checks don't require an ABA number from the recipient. The ABA number on a check belongs to the bank where the account holder has their account — the person writing the check. You only need an ABA number when you're setting up direct deposit or authorizing electronic transfers.
What if my bank doesn't have a routing number listed online?
Call the bank directly and ask for the routing number. Have your account number ready. If it's a very small credit union or community bank, you can also search the Federal Reserve database at frbservices.org with the bank's name and state.
Can the ABA number change?
Rarely. An ABA number stays the same for the life of the bank unless the bank merges with another institution. If your bank is acquired, you may be assigned a new routing number, and the bank will notify you. Your existing direct deposit arrangements may need to be updated with the new number.