A routing number in the United States is always 9 digits long for standard bank routing transit numbers.

Quick Scoop

  • A routing transit number (RTN) is a unique 9-digit code used to identify a bank or financial institution.
  • On paper checks, the routing number is the first 9 digits on the bottom left.
  • The 9-digit format is set by the American Bankers Association and is standard for U.S. banks.

So if you’re counting digits to see whether a number is a routing number, you should be looking for exactly 9 digits —no more, no less.

SEO notes (for your post):

  • Focus keyword: how long is a routing number (answer clearly in the first line).
  • Meta description idea: “Wondering how long a routing number is? In U.S. banking, routing numbers are always 9 digits, used to identify your bank for transfers, direct deposits, and payments.”

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