Paste any 9-digit ABA routing number below. We run the Federal Reserve’s official check-digit formula instantly in your browser — nothing is sent to a server — then match it against 5,679 credit union routing numbers on file.
Every valid US ABA routing number satisfies a public formula set by the American Bankers Association. Label the nine digits d₁–d₉. The number is valid only if:
3×(d₁+d₄+d₇) + 7×(d₂+d₅+d₈) + 1×(d₃+d₆+d₉) is a multiple of 10.
This check digit lets banks catch typos and transposed digits before a payment is ever sent — it cannot tell you whether a number is currently issued to an active institution, only whether it is well-formed. That’s why this tool does two checks: the math first, then a live match against our FedACH-sourced credit union directory.
A checksum pass means the digits could plausibly be a real routing number. It does not guarantee the number is currently active, or that it belongs to the institution you think it does — some numbers are retired after mergers, and this directory only covers credit unions, not banks. If your number checks out but isn’t found below, verify it directly with your financial institution or the Federal Reserve’s FedACH Participant Directory before using it for a transfer.
Looking for a specific credit union instead? Use the full directory search, browse all credit unions, or see our guide on how to find your routing number.