ABA Routing Numbers: What They Are and How to Verify Yours

You'll see your ABA routing number on every business check you ever order, but most people don't know what it actually identifies or why banks need it. If you're about to order checks or set up direct deposit and you're staring at a nine-digit number, this is what it means and how to confirm you have the right one.

What is an ABA routing number?

An ABA routing number is a nine-digit code that identifies the financial institution where your account lives. ABA stands for American Bankers Association, which has assigned routing numbers since 1910. Every US bank, credit union, and savings institution has at least one routing number. Larger banks have several.

The structure is consistent across every routing number. The first two digits indicate the Federal Reserve district where the bank is based. The next two digits identify the specific Fed branch. Then four digits for the bank, and a final check digit calculated from the previous eight.

When you write a check, the routing number tells the Federal Reserve where to route the payment for processing. When you receive an ACH deposit, the sender's bank uses your routing number to know where to send the money.

How do I find my ABA routing number?

Three ways, in order of reliability:

On an existing check. The bottom of a printed check has the MICR line in magnetic ink. The first nine digits, reading left to right, are the routing number. The next nine to twelve digits are the account number. The final set is the check number.

In your online banking portal. Almost every bank now shows the routing number on the main account page after you log in. Look for "Account Details" or "Account Information." The routing number sits right next to your account number.

By calling your bank directly. If you can't find an existing check and your online banking doesn't show it, the bank's customer service line will read it to you after verifying your identity. Not recommended for ordering checks because you want to read it yourself and confirm.

The least reliable source is a third-party routing number lookup website. They're often outdated and don't account for banks that have multiple routing numbers.

Why does my bank have multiple routing numbers?

Large banks have separate routing numbers for different purposes or different regions. Chase, for instance, has roughly 24 different routing numbers covering different states and account types. Bank of America has separate routing numbers for ACH versus wire transfers.

This matters because the routing number on your checks has to be the one your bank uses for paper check processing in your state. Using the ACH routing number on a paper check causes the check to bounce back through the Federal Reserve system, which can delay clearing by 1 to 3 business days.

To confirm you have the right routing number for paper checks, look at an existing check from the same account. The MICR line on that check is the one you want. Don't substitute the ACH or wire routing number that comes up on lookup sites.

How do I verify a routing number is correct?

Three checks you can do yourself:

Verify the check digit. The ninth digit is a checksum calculated from the other eight. There's a formula: multiply the first digit by 3, the second by 7, the third by 1, and continue cycling 3, 7, 1 through all nine digits. Sum the products. The result should be divisible by 10. If it's not, the routing number is wrong.

Use the Federal Reserve's E-Payments Routing Directory. It's free and lists every active routing number in the US. Type in your number and it should show your bank's name, address, and which payment types it supports.

Match it against your bank's published number. Most banks publish their routing numbers on their public website. Search "[Your bank name] routing number" and confirm the number on your check matches the published number for your state.

If any of these three checks fail, contact your bank before ordering checks. A wrong routing number on printed checks is the most common reason checks get rejected at deposit.

What happens if you order checks with the wrong routing number?

Two scenarios:

If the routing number is for a different bank entirely (typo, transposed digits), the checks get rejected when the recipient tries to deposit them. Their bank's automated processing returns the check with a "Cannot Locate Account" code. The check looks legitimate but functionally bounces.

If the routing number is for the right bank but wrong region or wrong account type, the check still clears but takes 1 to 3 extra business days. Annoying but not catastrophic.

Most check printers, including ours, will reprint at a discounted rate if you can prove the routing number error came from the printer (a typo at the printer's end). If you provided the wrong number on the order form, the reprint is at standard pricing.

How Checkomatic verifies your routing number before printing

Before any check ships from our facility, we run a three-part verification:

The routing number passes the ABA check-digit formula. If it fails, the order is paused for review.

The number matches an active entry in the Federal Reserve's E-Payments Routing Directory. If the directory shows the bank as inactive, the order is paused.

The bank name on the order form matches the bank name in the Fed Directory. If you wrote "Wells Fargo" but the routing number is for Chase, we pause and reach out.

This catches roughly 2 percent of orders before they ship. Most of those are honest typos. A few are accounts that were closed recently or routing numbers from old check stock that's no longer valid.

You see the verified routing number on the digital proof before printing. Confirming the proof matches a current check from your account is the most reliable final check.

When you order from our business checks catalog, the order form includes the verification step automatically. If something doesn't match, you'll hear from us before checks print.

Does my routing number ever change?

Rarely. Three situations where it can:

Bank merger or acquisition. If your bank gets acquired, your old routing number may transition to a new one over 12 to 24 months. The bank notifies account holders well in advance.

Charter change. If your bank changes its federal charter (state-chartered to national, for instance), the routing number can change.

Bank failure. If your bank fails and the FDIC transfers accounts to another institution, the new bank assigns new routing numbers.

In all three cases, the bank gives you a window where both routing numbers work. Use the transition period to reorder checks with the new number.

Frequently Asked Questions

Is the routing number the same on every check from my account?

Yes. Every check from the same account uses the same routing and account number. Only the check number changes.

Can I share my routing number publicly?

Routing numbers alone aren't sensitive. They're published in the Federal Reserve directory. Combined with your account number, they could be used to set up unauthorized ACH debits, so don't share both together.

What if my routing number on file at vendors is wrong?

Send an updated W-9 or direct deposit form with the correct number. Don't try to fix it by writing the correct number on existing checks.

Does Zelle use the same routing number as my checks?

For most banks, yes. A few banks use a separate routing number for Zelle. Check your bank's instructions if Zelle is failing for you.

Can two banks have the same routing number?

No. Routing numbers are unique to each financial institution. The same institution can have multiple routing numbers, but two different banks never share one.

You know your routing number now

When you order business checks, you'll need your routing number, account number, business name, and address. Have an existing check or your online banking open while you fill out the order form, and the verification step will catch most errors.

Browse our business checks catalog when you're ready, or read our how to order business checks online walkthrough for the full ordering process.

This article was written and reviewed by the Checkomatic team. Checkomatic manufactures business checks, envelopes, and related products on-premises in Monroe, NY, and serves thousands of small businesses across the US.