ABA Routing Number Validator
Validate US bank routing numbers with the checksum and Fed district.
About this tool
Paste one or more nine-digit routing numbers. Each is checked with the ABA checksum and its first two digits are decoded into a type (bank, thrift or credit union, electronic, government) and Federal Reserve district. If the checksum fails, the correct last digit is shown.
How routing numbers are validated
An ABA routing transit number (RTN) identifies a US financial institution for cheques, direct deposit, ACH and wire transfers. It's always nine digits, and the last is a checksum. Multiply the digits by the repeating weights 3, 7, 1 and add them up: 3 × (d1 + d4 + d7) + 7 × (d2 + d5 + d8) + (d3 + d6 + d9) must end in 0. That rejects any single mistyped digit and most transpositions, so validating before submitting a payment form avoids rejected transfers. The first two digits encode the Federal Reserve routing symbol: 01–12 for banks in the twelve Fed districts (01 Boston, 02 New York … 12 San Francisco), 21–32 for thrifts and credit unions, 61–72 for electronic-only routing, and 80 for traveller's cheques. 021000021 (JPMorgan Chase, New York) and 011401533 pass, while 123456789 fails. Honest limits: a valid checksum doesn't confirm the number is currently assigned, which bank it belongs to, or whether it accepts ACH or wires. Confirm with your bank or the Federal Reserve E-Payments Routing Directory. Not financial advice. The SWIFT/BIC validator and the check digit calculator are related.
Frequently asked questions
How many digits is a routing number?
Nine. The last digit is a checksum calculated from the first eight.
How do I validate a routing number?
3×(d1+d4+d7) + 7×(d2+d5+d8) + (d3+d6+d9) must be divisible by 10. The tool checks it instantly.
What do the first two digits mean?
The Federal Reserve district and type: 01–12 banks, 21–32 thrifts/credit unions, 61–72 electronic.
Is my data sent anywhere?
No. Everything is checked in your browser, and nothing is stored, looked up online or sent.