How to Verify a Routing Number

Why Verification Matters

An invalid or incorrect routing number can cause your payment to be rejected, returned, or — in rare cases — misdirected. Before sending a wire transfer, setting up direct deposit, or making a large ACH payment, it is worth taking 60 seconds to verify that the routing number you have is valid and belongs to the institution you expect.

Method 1: Use the ABA Checksum Formula

ABA routing numbers include a built-in mathematical check digit — the ninth and final digit. You can verify that a routing number has valid formatting by running the checksum calculation yourself.

How the ABA checksum works:

1. Multiply each of the first eight digits by the corresponding weight: 3, 7, 1, 3, 7, 1, 3, 7
2. Add all eight products together
3. The result must be divisible by 10 (i.e., the remainder when divided by 10 must be 0)

Example: Verify routing number 021000021

• 0×3 = 0
• 2×7 = 14
• 1×1 = 1
• 0×3 = 0
• 0×7 = 0
• 0×1 = 0
• 0×3 = 0
• 2×7 = 14
• Sum of first 8 weighted digits = 29
• Add check digit: 29 + (1×1) = 30
• 30 ÷ 10 = 3 with remainder 0 → Valid

If the checksum does not work out to a multiple of 10, the routing number has a typo or is fabricated.

Method 2: Look It Up in the Federal Reserve Directory

The Federal Reserve maintains the authoritative database of all active ABA routing numbers through its FedACH Directory and Fedwire Directory, both available at frbservices.org. If a routing number does not appear in the Federal Reserve directory, it is either inactive, invalid, or fraudulent.

You can also look up routing numbers on this site — every routing number in our database comes directly from the Federal Reserve's FedACH directory and is updated regularly.

Method 3: Contact the Bank Directly

If you received a routing number from someone you do not know — for example, in a check you received from an unfamiliar source — call the bank directly using a phone number you find on the bank's official website (not the number on the check). Ask the bank to confirm that the routing number is valid and that the account is active. Banks cannot share account balance information, but they can confirm whether an account exists.

Red Flags That Suggest a Fraudulent Routing Number

• The routing number fails the ABA checksum calculation
• The routing number does not appear in any public database or on this site
• The bank name associated with the routing number does not match what the sender told you
• The routing number is associated with a bank in a state or region that does not match the context

What to Do If You Sent Money to the Wrong Routing Number

If you initiated an ACH transfer with the wrong routing number, contact your bank immediately. ACH transactions can sometimes be reversed or recalled within the first few business days, but there is no guarantee. For wire transfers, which settle immediately and are generally irreversible, contact your bank right away and ask them to initiate a wire recall — the success rate depends on how quickly you act and whether the receiving bank cooperates.