NAICS Codes for Contractors: How to Pick Yours

Quick answer

A NAICS code is a six-digit number that classifies your business by its primary industry. In government contracting it does two important jobs: it helps match your company to the right opportunities, and it sets the small-business size standard that decides whether you qualify as "small" — and therefore for set-asides — on a given contract. Picking the right codes is a quick step that shapes what work you get matched to for years.

What NAICS codes actually do

NAICS — the North American Industry Classification System — is the standard way governments categorize businesses by industry. In procurement, your codes do two things. First, buyers and matching tools use them to find vendors that do the kind of work being bought. Second, and just as important, every NAICS code carries an SBA size standard: a maximum annual revenue or employee count that defines a "small business" in that industry. Because each solicitation is assigned a NAICS code, whether you count as small — and can compete for that opportunity's set-aside — depends on the size standard tied to that specific code.

Primary vs. secondary codes

You choose one primary code — the industry that represents most of your revenue — plus as many secondary codes as genuinely describe the other work you self-perform. A roofing contractor might carry 238160 (Roofing Contractors) as primary and add related codes only if they truly do that work. There's no advantage to padding your list with codes for work you can't actually deliver; it just leads to poor matches and bids you can't win.

How to pick your codes

• Start with your core trade — the single code that best describes most of your revenue becomes your primary.
• Add secondary codes for other work you self-perform (a GC might add specific trade codes they keep in-house).
• Look up each code's SBA size standard so you know where you stand as a small business for that type of work.
• Check the codes competitors and past awards in your space use — search historical awards to see which NAICS codes buyers actually assign to the work you want.
• Set them in SAM.gov and revisit as your business changes.

NAICS vs. PSC

It's easy to confuse the two codes on a solicitation. A NAICS code classifies you — your industry as a seller. A Product/Service Code (PSC) describes what's being purchased. A solicitation typically shows both: the NAICS code (which sets the size standard and matches vendors) and the PSC (which categorizes the actual product or service). You set your NAICS codes; the PSC comes from the buyer.

Setting up your codes is part of registering to bid — see the SAM.gov registration guide for where they fit in the process.