Routing Number Validator

Validation is instant and simple:

Enter the routing number. Type or paste any 9-digit number. The tool validates as you type and shows real-time feedback.

View the result. A valid routing number shows a green checkmark with the Federal Reserve district and transfer type. An invalid number shows the checksum calculation so you can see exactly where the error is.

Understand the breakdown. The tool shows: digits 1-2 (Federal Reserve district), digits 3-4 (routing center), digits 5-8 (institution identifier), and digit 9 (check digit).

Key features:

• Official ABA checksum — uses the weighted modulus-10 algorithm
• Federal Reserve identification — maps first 2 digits to the processing center
• Transfer type detection — electronic (ACH), wire, or check processing
• Step-by-step math — shows the full checksum calculation

The ABA routing number uses a weighted modulus-10 check digit scheme. For a routing number with digits d1 d2 d3 d4 d5 d6 d7 d8 d9:

The checksum formula is:

(3×d1 + 7×d2 + 1×d3 + 3×d4 + 7×d5 + 1×d6 + 3×d7 + 7×d8 + 1×d9) mod 10 = 0

The weights 3, 7, 1 repeat for each group of three digits. If the total sum modulo 10 equals zero, the routing number is mathematically valid.

Example: For routing number 021000021 (JPMorgan Chase):

• 3×0 + 7×2 + 1×1 + 3×0 + 7×0 + 1×0 + 3×0 + 7×2 + 1×1 = 0 + 14 + 1 + 0 + 0 + 0 + 0 + 14 + 1 = 30
• 30 mod 10 = 0 ✓ Valid

Note: A valid checksum confirms the number is structurally correct, but doesn't guarantee it's assigned to an active bank. For that, you would need to check the Federal Reserve's official routing number directory.

Each part of the 9-digit routing number has a specific meaning:

• Digits 1-2: Federal Reserve District — Identifies which of the 12 Federal Reserve Banks processes the institution's transactions. Ranges from 01 (Boston) to 12 (San Francisco). Numbers 21-32 indicate electronic (ACH) transfers. Numbers 61-72 are used for wire transfers.
• Digits 3-4: Federal Reserve Office — Identifies the specific Fed branch within the district.
• Digits 5-8: Institution Identifier — The unique identifier assigned to the financial institution by the ABA.
• Digit 9: Check Digit — Calculated using the weighted modulus-10 algorithm to catch transcription errors.

A single bank may have multiple routing numbers for different purposes (ACH vs. wire vs. check) or for different states. Always verify you're using the correct routing number for your specific transaction type.