Routing Number Validator
Validate a nine-digit ABA routing number against its checksum and see which Federal Reserve district issued it. Runs in your browser — resolving the number to a bank name is what the Routing Number Lookup API adds.
- Runs in your browser
- No sign-up
- Free API available
- Same result as
- Routing Number Validator API
- Category
- Validation
- Cost
- 5 credits / call
- This page
- 100% client-side
Try it — no sign-up
Check any US bank routing number.
Routing number
Output
Check any US bank routing number against the ABA checksum and see which Federal Reserve district issued it.
Everything runs locally in your browser — nothing is uploaded. Need it in your app? Use the Routing Number Validator API.
How is a routing number validated?
The nine digits carry a weighted checksum: three times the first, fourth and seventh, plus seven times the second, fifth and eighth, plus the third, sixth and ninth. A valid number is divisible by ten. The tool also checks that the leading two digits fall in a range the Federal Reserve actually issues.
Does a valid checksum mean the bank exists?
No, and this is the common misconception. The checksum proves the number is well-formed and correctly issued — it cannot tell you whether the institution is still operating or has merged. Confirming the bank requires the routing directory, which is what the API queries.
Can I get the bank name from a routing number?
Not from the digits alone — there's no formula, only a directory. The Routing Number Lookup API returns the institution name, address, and status for a given routing number.
What do the first two digits mean?
They identify the issuing Federal Reserve district — 01 through 12 for commercial banks from Boston through San Francisco, 21 to 32 for thrift institutions, and 61 to 72 for electronic-only transactions. The tool names the district for you.
Is my input sent anywhere?
No. Both the checksum and the district come out of the digits themselves, so the whole check runs locally in your browser. Nothing is transmitted, logged, or stored.