NAICS codes are six digit numbers that label what industry your business is in. They sound like a formality, but they quietly control two things that matter to you every day you spend looking for federal work: what opportunities you get matched to, and what counts as small for you when a size standard applies.

1 · Understand what the code actually controls

Every notice on SAM.gov carries a primary NAICS code, and it is the main way agencies and search tools sort work by industry. Your registration lists your own NAICS codes, and matching between the two is a first filter buyers and search tools use, before anyone reads a word of what you actually do. The same code also sets your size standard: whether your business counts as small depends on the ceiling for that specific code, not a general sense of your size. See size standards for how that ceiling actually works.

2 · Separate your primary code from your additional codes

SAM.gov asks for one primary NAICS code, the one that best describes your main line of business, plus room for additional codes covering other things you legitimately do. The primary code carries the most weight, so choose it as the industry a stranger would guess you are in after reading your invoice history, not the one that sounds most impressive.

3 · Pick codes for what you actually do, not what you wish you did

Claiming a code for work you do not really perform is a real risk, not a shortcut. If you win a contract under a code that does not reflect your actual capability or size, that gap can surface later, during a size protest or a performance review. List the codes that match your invoice history and your staff's actual skills.

4 · Look up the actual list

NAICS codes are maintained by the Census Bureau and revised on their own schedule, so search the current code list rather than reusing a code you remember from years ago. SAM.gov also runs its own lookup during registration, which is usually the faster path if you already know roughly what you are searching for.

5 · Revisit the list yearly

Businesses add services, drop others, and the code list itself gets revised on its own schedule. A code that fit when you first registered can quietly stop matching what you actually sell. Treat this the same way you treat any other registration fact: worth a few minutes once a year, not something you set once and forget.

If typing through the full code list sounds like a chore, it is one you can skip. With a free Quarry account, you describe what your business actually does in plain English during setup, and we map that description to the NAICS codes for you.