NAICS Codes Explained: Find Yours in Five Minutes

Every government bid is tagged with a NAICS code — a six-digit label for the kind of work being bought. Agencies use it to describe what they need, and contractors use it to filter the flood. Get your codes right and the right bids find you; get them wrong and you're invisible.

How the six digits work

NAICS (North American Industry Classification System) is a hierarchy — each pair of digits narrows the field:

• 23 — Construction (sector)
• 2371 — Utility System Construction
• 237130 — Power and Communication Line Construction

A bid tagged 237130 is buying exactly what a fiber or power-line crew sells. Two companies in the same sector can live in completely different bid universes.

Finding yours, the fast way

• Start from what you sell, not what you're called. "We're a technology company" means nothing; "we install fiber optic cable" is 237130. List your three most common revenue sources and code those.
• Use the Census lookup. The official NAICS search at census.gov lets you keyword-search plain descriptions ("electrical contractor" → 238210).
• Learn from your competitors. Search USASpending.gov for companies like yours — every award lists the NAICS code it was bought under. Five minutes of that teaches you more than an hour of guessing.

Primary code vs. every other code

Your SAM.gov registration has one primary NAICS code — it sets your small-business size standard, which decides which set-aside contracts you qualify for. But you can list additional codes, and you should: every code you add is another filtered lane of bids you're eligible to see and win.

One warning: codes get revised

NAICS codes are updated every five years. Wired telecom carriers, for example, moved from 517311 to 517111 in the 2022 revision — anyone still filtering only on the old code silently lost years of opportunities. When your bid flow feels thin, check that your codes are still current.