How To Find and Use ABA Numbers
You can get your account’s ABA number from several sources. The easiest solution is to locate the numbers at the bottom of one of your checks if you have a checkbook handy.
On Paper Checks
An ABA number is printed on every check. It’s usually the nine-digit number in the bottom left-hand corner on personal checks. The number might appear somewhere else on computer-generated checks (like online bill payment checks or business checks).
Contact Your Bank
Some banks provide this information online, although you might need to log into your account to find the right number. Search your bank’s website for direct deposit forms or Automated Clearing House (ACH) information. Alternatively, call customer service and ask.
Use the Correct Number
Your bank may operate under several ABA numbers, so it’s essential to identify the one specific to your account. ABA numbers may differ slightly depending on where you opened your account, and bank mergers can result in multiple codes for the same bank. Some banks also use separate ABA numbers for wire transfers vs. direct deposit or ACH transactions. You might have to use a different number for wire transfers or electronic bill payments even if you know the correct number for ordering checks. When in doubt, ask a customer service representative at your bank which number to use.
How ABA Numbers Work
All you have to do is provide your ABA number, along with your account number, to whoever is requesting it in most cases. Banks, billers, and your employer (or whoever else is setting up automatic transfers) can handle the logistics after that. Ask your bank if you can continue using the old numbers until you order new checks or sign up for new services. You can continue using old routing numbers indefinitely in some cases. ABA numbers follow an intricate system:
Behind the Name
An ABA number is like an address that tells financial institutions where to find your account. ABA numbers may also be called routing transit numbers (RTNs) or check routing numbers for this reason.
They’re Computer-Readable
Routing numbers are typically printed on checks using magnetic ink, which allows special machines to read the code more easily. Printers usually use MICR font regardless of whether magnetic ink is present, making it easy for computers to visually recognize the numbers. This can be helpful when you deposit a check by snapping a photo with your mobile device. The first four digits are made up of the Federal Reserve Routing Symbol. The first two digits have different meanings based on their series. The ABA outlines each series on its website. The next four digits are the ABA institution identifying digits. The ninth digit provides a checksum or check digit. This is a complicated mathematical expression using the first eight digits. The transaction gets flagged and rerouted for manual processing if the end result does not equal the checksum number.
History of the ABA Number
The American Bankers Association (ABA) created ABA numbers in 1910 as a way to assign unique identifiers to each payment-issuing bank. Doing so reduced confusion for processing paper checks, which were the common form of payment at the time. ABA numbers have evolved over time to include the Federal Reserve’s payment processes and facilitate modern electronic payments.
How ABA Numbers Help Process Checks
The ABA number has played an instrumental part in speeding up check processing since the 1960s. Additionally, physical checks that needed to travel by airplane and truck to reach banks could now be submitted and cleared electronically with the passage of the Check 21 Act in 2003. Funds clear much more quickly as a result, and consumers no longer have the luxury of “playing the float” or issuing a check a few days before they actually have the funds in their account.
