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NAICS and PSC codes explained
NAICS codes classify what industry you are in; PSC codes classify what the government is buying. Together they determine which opportunities you see, whether you count as small, and whether agencies can find you.
Two code systems, two questions
Federal procurement uses two classification systems that new contractors constantly mix up. NAICS (North American Industry Classification System) codes answer the question 'what industry is this work in?' — they are six-digit codes maintained by the Census Bureau and used across the whole US economy, not just government. PSC (Product Service Code) answers 'what specific product or service is being bought?' — a four-character code used only in federal procurement.
A single solicitation carries one NAICS code (which sets the size standard for the competition) and one PSC (which categorizes the purchase for reporting and search). As a seller, you will use NAICS to define your identity and eligibility, and both codes to filter the opportunity stream.
How agencies use NAICS
When a contracting officer prepares a solicitation, they assign the single NAICS code that best describes the principal purpose of the work. That code determines the size standard: the revenue or employee ceiling under which a bidder counts as a small business for that competition. The same company can be small under one code and not under another, because standards vary widely by industry.
Size standards come in two flavors: average annual receipts (calculated over your most recent five completed fiscal years) for most services and supply industries, and average employee count for most manufacturing. SBA publishes the full table and a lookup tool — check it rather than guessing, because standards are revised periodically.
Choosing your NAICS codes
In SAM.gov you list one primary NAICS code and as many secondary codes as genuinely apply. The primary code should reflect where most of your revenue comes from; secondaries capture other lines of business. There is no fee and no limit worth worrying about, but padding your profile with codes you cannot perform dilutes your credibility with the buyers and primes who look you up.
Importantly, your registered codes do not limit what you may bid on. You can compete on any solicitation whose work you can actually perform — eligibility for a small business set-aside depends on the size standard of the code on that solicitation, not on whether the code appears in your profile. Your profile codes mainly affect how you are found in market research.
How PSC codes work
Product Service Codes describe the thing being purchased: codes beginning with a digit are products (for example, medical and surgical instruments fall in the 65xx family), while codes beginning with a letter are services (R for professional support services, S for utilities and housekeeping, D for IT services, and so on). GSA maintains the PSC manual.
Because PSC describes the purchase rather than the vendor, it is often a sharper search filter than NAICS. Two solicitations in the same NAICS can be for very different things; the PSC usually tells you which one is actually your product.
Using both codes to find opportunities
The practical workflow: build saved searches that combine your NAICS codes and the PSC families that match your catalog, then refine by set-aside type, agency, and place of performance. Casting the net with NAICS alone tends to produce noise; PSC alone can miss miscategorized postings — agencies do not always code things the way you would. Using both, plus keywords, gives the best coverage.
This is exactly what Govetract automates: your catalog is mapped to the relevant codes, live SAM.gov postings are matched against it, and each opportunity is scored so you spend time on the ones worth pursuing rather than on triage.
Codes and your size status over time
As you grow, watch the size standards in your key codes. Outgrowing a standard means losing access to set-asides under that code — a milestone worth planning for rather than discovering mid-proposal. Note that after certain events (like being acquired) or at certain contract points, you may have to re-represent your size.
Also know that a NAICS code assigned to a solicitation can be challenged: if an agency picks a code that clearly does not fit the work (and the size standard shuts you out), there is a formal, deadline-driven appeal process through SBA. New contractors rarely need it, but knowing it exists helps you understand why code selection is taken seriously.
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