Definition
The nine-digit code identifying a U.S. bank or credit union in the payment system, used with your account number for direct deposit, ACH transfers, and checks. The routing number identifies the institution; the account number is the private half of the pair.
Why it matters
Direct deposit forms, tax refunds, and autopay setups all fail on a mistyped routing or account number, and money sent to the wrong account is slow to recover. Anyone holding both numbers can attempt withdrawals, so the account number deserves password-level care.
Example
Setting up direct deposit, an employee copies the nine-digit routing number and account number from their bank's app instead of an old check. Payday lands in the right account on the first cycle, with no paper check stopgap needed.
Related terms
This definition is educational, not financial, legal, or tax advice. U.S. rules and limits change; verify time-sensitive details with official sources. See our disclaimer.