What Is a Bank ABA Number?

Many people have likely seen routing numbers printed on the bottom of checks or heard banking terms like “ABA routing number” thrown around before. However, there remains confusion regarding what an ABA number specifically refers to, how it differs from a routine routing number, and when you actually need to provide it. This article clarifies precisely what an ABA number is, when it’s required, and how to easily look it up.

What is a Bank Routing Number?

Before getting into the specifics of ABA numbers, it helps to understand bank routing numbers in general. A routing number is a 9-digit code that identifies a bank or financial institution. The routing number helps facilitate processing of financial transactions like direct deposits, checks, and wire transfers.

When you write a check or set up a direct deposit, the routing number provides instructions on where those funds should be pulled from or deposited into. It essentially routes the money to the correct bank. Routing numbers are also referred to as “transit numbers.”

Every bank has at least one routing number but may have several across different states, branches, and departments. Large multinational banks like Citi and Chase have multiple routing numbers. The first two digits of routing numbers signify the Federal Reserve district the bank resides in.

What is an ABA Number?

An ABA number refers specifically to a bank routing number that belongs to an institution that is a member of the American Bankers Association or ABA. The ABA is an organization that represents banks and financial institutions within the United States. If a bank is an ABA member, it means it’s a valid, legitimate institution subject to additional oversight and regulatory compliance standards.

So in short, an ABA number is simply a routing number that has been designated specifically to banking institutions that are members of or affiliated with the American Bankers Association. This means all ABA numbers are routing numbers, but not necessarily vice versa.

ABA routing numbers follow a specific format. They are nine digits like regular routing numbers, but the first two digits fall between 01 and 12.

When You Need to Provide an ABA Number

There are several common situations where you need to provide a bank's ABA routing number rather than a generic routing number, such as:

Setting Up Direct Deposits

When setting up direct deposit of your paycheck, government benefits, tax refunds, or other regular payments, institutions typically ask for the ABA routing number associated with your bank account. This helps ensure funds get deposited into legitimate member bank accounts.

Wiring Money Domestically

Sending domestic bank wires within the United States also often requires an ABA routing number to provide accurate account instructions. Wires sent using ABA numbers also tend to have higher transaction limits.

Ordering New Checks

When purchasing additional checks from your bank or a third-party printer, you need to provide the ABA routing number so it can be printed accurately on the checks for processing.

Other Cash Transfers

Any transactions involving physical checks or cash transfers often depend on ABA routing numbers to route transfers through the clearinghouse system. ACH transactions also utilize ABA routing information even if no physical checks are involved.

How to Find Your Bank's ABA Routing Number

If you aren’t sure if you have your bank's proper ABA routing number on hand for transfers or check orders, there are a few quick ways to find it:

On The Bottom of Physical Checks

Your physical checks should have the 9-digit ABA number clearly printed on the bottom left corner. Make sure to use the number on your most recent check orders.

Your Bank's Website

Many bank websites post the official ABA routing number online for easy reference. It’s often under routing number listings or FAQs. Double check it’s noted as the ABA number.

Call Customer Service

Calling your bank's customer service allows you to ask an associate to confirm the correct ABA number on your account. Let them know you need it for deposits, transfers or reordering checks.

ABA Number Lookup Tools

Both the Federal Reserve and American Bankers Association offer ABA routing number lookup tools to find your bank’s number. You simply select your state and bank by name. Just make sure to cross-reference any numbers listed on your own account’s checks.

The Bottom Line

Hopefully this provides more clarity regarding what an ABA routing number is and when you're likely to need it. The key takeaways are that ABA refers specifically to numbers associated with American Bankers Association member institutions, all ABA numbers are routing numbers but not vice versa, and you may need to provide ABA digits when dealing with physical check transfers, deposits, and wires. Check your existing checks or call your bank directly whenever unsure of the appropriate ABA number for transactions.