Free ACH Routing Number Validator

What is ACH?

ACH stands for Automated Clearing House — the electronic network that processes the vast majority of domestic bank transfers in the United States, including direct deposit payroll, tax refunds, and recurring bill payments. Operated under Nacha rules, the ACH network handles over 30 billion transactions a year and is the standard, low-cost way to move money between US bank accounts.

Routing number format

Every US bank account is tied to a 9-digit ABA routing number (also called an ACH routing number) that identifies the specific bank and Federal Reserve processing district. The first two digits are the Federal Reserve routing symbol — valid ranges are 01–12 (Federal Reserve Bank districts), 21–32 (thrift institutions), 61–72 (electronic transactions), or 80 (traveler's cheques). Digits 5–8 identify the specific institution, and the 9th digit is a checksum.

The ABA checksum

The final digit of a routing number isn't arbitrary — it's calculated using a specific weighted formula: 3×(d1+d4+d7) + 7×(d2+d5+d8) + 1×(d3+d6+d9), and the total must be evenly divisible by 10. This checksum, defined by the American Bankers Association, catches the vast majority of typos and transposed digits before a payment is submitted — exactly what Banqcheq checks for you automatically.

Federal Reserve districts

The United States is divided into 12 Federal Reserve districts, and the first two digits of a routing number map to one of them — for example, 02 is New York, 01 is Boston, and 12 is San Francisco. This district information is baked into the routing number's own checksum validation and confirms the number was issued through a legitimate Federal Reserve processing channel.

ACH vs wire transfer

ACH transfers are cheaper (often free) but slower — typically 1–3 business days, or same-day for an extra fee. Wire transfers (via Fedwire domestically, or SWIFT internationally) are faster, often same-day or real-time, but usually carry a fee of $15–50 per transfer and are irrevocable once sent. For everyday payments like payroll or vendor invoices, ACH is the standard choice; for urgent or time-sensitive payments, a wire transfer is usually worth the extra cost.

Common routing number errors

The most frequent mistake is confusing a routing number with an account number — they're both strings of digits and easy to swap by accident, especially when copying from a check where the routing number comes first. Another common error is using a wire transfer routing number where an ACH routing number was needed — some larger banks issue a different routing number for each purpose, printed separately on statements. Banqcheq's checksum check catches simple digit errors instantly, but always confirm which type of routing number your recipient actually needs.