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Is an ABA Number the Same as a Routing Number?

It may seem like checks are going the way of the dinosaur in exchange for apps like Venmo and Google or Apple Pay, but some transactions require the old school method. Of course, there are all sorts of numbers on your checks, but knowing what they mean can certainly be confusing.

The ABA number on a check is generally the same as the routing number, but that is not always the case. Some banks use several ABA numbers or separate numbers for wire transfers, ACH transactions, and direct deposits. Still, the ABA number is your routing number for the most part, but you may see it in two different forms and places on your check. You should contact your bank to see how their system works.

There are quite a few digits on the front of a check, including a routing or ABA number, your account information, and the number of the check. These numbers can differ based on the financial institution and the type of monetary exchange taking place. Keep reading to learn more.

The Difference Between an ABA Number and a Routing Number 

While the question is straightforward enough, the answer can be a little bit confusing at first glance. Plenty of articles and forum answers indicate that your routing number is exactly the same as the ABA number. And it is — for the most part.

But it isn’t as easy as a yes or no because there are actually two different identifying numbers and terms, each with the ABA acronym — the ABA routing number, found on the bottom left of a check, and an ABA identification or transit number that you’ll sometimes find in fraction form at the top of your check. 

While both of these numbers often contain many of the same digits and their purpose is essentially the same, they do appear differently. Additionally, there are instances where the ABA number and the routing number you need may differ depending on your bank and the type of transaction.

First, though, let’s take a look at what an ABA number is and where you’ll find it.

What Is an ABA Number? 

The two most important codes or numbers that you’ll find on a check include the ABA Transit or Routing Number, which we also simply call the ABA number or RTN number, and your account number, which is specific to you.

The purpose of an ABA number is to identify financial institutions in the United States. The American Bankers Association developed these numbers in 1910, thus the ABA acronym (source). 

You can think of the ABA number as your bank’s numerical address and your account number as the individualized address where your personal money resides.

The purpose of ABA numbers is to organize the flow of checks going back and forth, identifying who is responsible for the funds each exchange represents. 

If you can imagine checks continually moving between banks and individuals, we can only describe the processing as equally cumbersome and confusing. These numbers solved that problem, uniquely identifying each payment-issuing bank.  

When you hear the phrase “ABA Number,” you’ll find that many banks use it interchangeably with the routing or RTN (routing transit) number, and that is not wrong. Remember, the main purpose of the number is simply to identify the financial institution from which you would draw a payment.

Now that we’ve moved to online banking as the primary method of funds transfers, the number is essential to maintain accuracy and accountability. 

But as we said earlier, you can find the ABA number in two places on most checks — one of which is generally one and the same as your routing number, and the other, which is not necessarily the same thing, though it will contain the same numbers in a different format but for a different purpose. 

Finding Your Bank’s ABA Number

On the bottom left of your check — as well as your deposit slips — you’ll find a nine-digit number in MICR form. MICR stands for “Magnetic Ink Character Recognition.” It allows your financial institution to process checks electronically, reading and recording information without having to do so manually.

That number is the ABA number, again, also known as your routing number.  

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Understanding what ABA Numbers Represent

The first four digits represent your bank’s physical location. But, as you probably are already aware, bank mergers happen frequently. Some banks no longer have physical locations and are wholly internet-based. 

With that in mind, most of the time, these numbers do not necessarily correlate to the bank’s physical or geographic location.

The next two numbers represent the Federal Reserve Bank that your bank’s electronic and wire transfers route through. 

The Federal Reserve System is the central bank of the United States. Congress established the Federal Reserve in 1913 to ensure a stable financial system, protecting Americans’ credit rights, and regulating banks and other financial institutions (source). 

The seventh number is the Federal Reserve check processing center that the Fed first assigned your bank to. The eighth number reflects the Federal reserve district, essentially communicating the Federal Reserve district location for your bank. 

The last number is an important one, which they call the “checksum” number.” A checksum is an incredibly complex mathematical equation that uses the first eight numbers to verify the authenticity of the check — or in other instances, other data (source). 

The end result of that checksum mathematical expression should equal the checksum number. If it does not, the check and transaction each get “flagged,” resulting in a reroute for manual processing. 

You’ll find a similar checksum identifier on your credit card, and its purpose is also to act as a “flag” for detecting errors, verifying data, and preventing fraud.  

When this process flags a check for manual processing, another ABA number is necessary, and that is the one that you’ll find in fraction form at the top of your check.

ABA Numbers in Fraction Form

If we rewind to the beginning of this article and reflect on the question as to whether or not your routing and ABA numbers are the same, here is where a “yes and no” answer can come into play.  

Before electronic processing, bankers had to manually process checks — an arduous process indeed. On many checks, you’ll find a second ABA Transit number in fraction form at the top.  

Today, this number is necessary as a backup number, just in case the machine-readable RTN or routing number is, for some reason, unreadable. The MICR format allows computers to read and recognize those identifying numbers; the fraction form at the top is not machine-readable, though it does contain most of the same information.

In fraction form, the top number or numerator is the ABA number, and the bottom number, the denominator, is the bank’s check routing number or symbol. That number identifies the Federal Reserve Bank that provides service to your financial institution. Often, these ABA numbers or fractions are 12 digits in total.  

The top number is similar to the routing number in that it identifies the physical location of the bank and identifies the bank itself, while the bottom number identifies the Federal Reserve Bank servicing the financial institution.

What Is a Routing Number?

Now that we’ve gone through what an ABA number is and answered whether it is the same as a routing number, the answer to this question is simple enough — your routing number is essentially the ABA number, the one you’ll find at the bottom of your check on the left side. 

The reason this number is so important is that it would be impossible to make any kind of electronic transfer without it. 

It allows for the movement and transaction of electronic checks and online payments, a much more useful and convenient method than paper checks, which may eventually disappear altogether. Gone are the days when balancing a checkbook by hand was necessary.

So, your routing number is indeed the ABA number. Many banks (and people) use these terms interchangeably now that we’ve moved to more frequent electronic processing of checks and other forms of wire transfers.

The ABA number that formerly existed only at the top of your check and was not machine-readable now exists at the bottom and identifies the routing path of your check and your financial institution. 

Bankers often call the nine-digit routing number the ABA RTN, which stands for American Bankers Association Routing Transit Number. In most cases, the state or branch where you opened the account determines the routing number.

Differences and Changes in Routing Numbers

Where this gets tricky is that, for some banks and financial institutions, there are different routing numbers depending on the type of transaction you want to complete. 

You may actually have a different routing number for your checking account versus a direct deposit transaction or ACH or wire transfer. If you are uncertain, the best thing to do is contact your bank directly to determine the correct routing number. 

One more note before we move on is that routing numbers do change from time to time. When banks merge, which happens more frequently now than in the past, your routing number may change as well.  

Your financial institution will notify you, however, and provide plenty of time for you to obtain new checks if necessary. And for the most part, banks will allow you to use the old routing number for a predetermined amount of time or until your checks run out.

You will need to change over any direct deposit numbers and other automatic transactions at some point, so it’s a good idea to review your bank statements and complete new, updated paperwork. 

ABA Routing Versus ACH Routing Numbers 

We’ve mentioned ACH numbers a few times thus far. If you’re wondering what “ACH” stands for, it is “Automatic Clearing House.” You may need this number for specific electronic transfers of payments that you want to set up as recurring or to make a one-time payment, including direct deposit payments and debits. 

There’s no need to get too overwhelmed by which number you’ll need when. ABA numbers, in general, encompass all routing numbers, including ACH numbers and wire transfers that occur within the US.

Most of the time, the ABA number that you’ll find on your check is the same number that you’ll use for ACH payments, specifically wire transfers and direct debit or deposit. But, as we said earlier, that is not always the case.  

Some banks have different numbers depending on the type of transaction. A wire transfer, for example, can be international, while an ACH transfer is limited to the US only, which in turn may necessitate different routing numbers. 

The complicating factor is that these changes in numbers differ by bank. You may be able to use the ABA routing number for all transfers of money. 

You certainly can for paper checks, but when it comes to electronic transfers, direct deposit or debit, or international transfers, you’ll need to check with your specific bank and branch to determine whether you need a separate number. 

The format of an ACH number is the same. It is 9 digits long and likely begins with a 61 or a 72. 

The Bottom Line

To sum it all up, the nine-digit ABA routing number on your check is the number you’ll need for most paper transfers and even most electronic payments, debits, and other monetary transfers. 

But again, you’ll need to check with your bank to determine if you need a separate ACH number for some of these other types of transfers, including wire transfers within the US. If you need to transfer money outside of the US, you likely need a different number altogether, so contact your bank to determine what that number is. 

Here’s a basic overview of ABA versus ACH numbers:

All ACH numbers are ABA routing numbers: they are both a numerical identification system, but not all ACH routing numbers are ABA routing numbers.

ACH numbers are not always the same as your ABA routing number: check with your individual bank to determine if they are the same or if they are different.

The ABA routing number on your check may be separate from what you’ll need for wire transfers and other forms of electronic payments. Again, check with your bank to be certain. This article was written for

The takeaway, regardless of the differences in these numbers — which can be incredibly confusing — is to simply contact and verify with your bank before you move money around. 

Final Thoughts 

There’s no doubt that all of these numbers and knowing which to use when can feel overwhelming. The good news is that you don’t have to figure it out on your own. Remember that an ABA number is essentially the same as your routing number — the nine-digit code at the bottom left of your check.

But before you make electronic transfers, check with your bank. They will always be able to provide you with the number you need to set up wire transfers, make payments, and set up direct deposits and debits.  

And after all this talk of numbers, if you are interested in learning more about mathematical figures, equations, and numbering systems — take a look at “Is Zero an Irrational or Rational Number?”