How to Find Your NAICS Code for SAM.gov Registration

A practical walkthrough for choosing your primary NAICS code, adding secondary codes, and understanding how SBA size standards affect your small business status. Registering on SAM.gov is free — never pay anyone for it.

If you want to sell to the U.S. federal government, you have to register your entity on SAM.gov, and at some point in that process the system asks for your NAICS codes. For many first-time registrants this is where things stall: there are over a thousand six-digit codes, the descriptions sound bureaucratic, and picking the "wrong" one feels risky. The good news is that the logic behind choosing a code is simple once you understand what NAICS is actually used for.

Before anything else, one point that cannot be repeated enough: registering on SAM.gov is completely free. The official site is sam.gov, and it charges nothing to create a Unique Entity ID (UEI), register your entity, or renew your registration each year. Plenty of third-party companies send official-looking emails or letters offering to "complete your SAM registration" for hundreds of dollars. Some are legitimate consultants; many are predatory. You never need to pay to be registered.

What NAICS means in the SAM.gov context

NAICS is the North American Industry Classification System, a six-digit coding scheme developed jointly by the United States, Canada, and Mexico to classify business establishments by their primary economic activity. In the U.S. it is maintained by the Office of Management and Budget with the Census Bureau, and it is revised every five years (the 2022 edition is the current one).

The six digits are hierarchical: the first two identify the sector (for example, 54 is Professional, Scientific, and Technical Services), the third the subsector, the fourth the industry group, the fifth the NAICS industry, and the sixth the national industry. So 541511 — Custom Computer Programming Services — sits inside sector 54, subsector 541, industry group 5415, and so on.

In federal contracting, NAICS codes do three jobs:

• They describe your business in your SAM.gov entity record, so agencies and prime contractors doing market research can find you.
• They classify every solicitation. A contracting officer assigns exactly one NAICS code to each procurement, based on the principal purpose of the work.
• They determine small business size standards. The Small Business Administration (SBA) publishes a size standard for every NAICS code, and whether you count as "small" for a set-aside contract depends on the code assigned to that solicitation.

Step 1: Find candidate codes for what you actually do

Start by describing your business in plain words — "commercial janitorial services," "sheet metal fabrication," "IT staffing" — and search for matching codes. You can use our free NAICS code lookup tool to search by keyword and browse descriptions, or the Census Bureau's official NAICS pages. Read the full description of each candidate code, not just the title: NAICS classifies establishments by how they produce something, so two businesses selling similar things can land in different codes (a bakery that bakes and sells on-site is classified differently from one that manufactures for distribution).

If your business is older and you only know your SIC code — the four-digit system NAICS replaced in 1997 — our SIC to NAICS converter maps legacy codes to their modern equivalents as a starting point.

Step 2: Choose your primary NAICS code

SAM.gov asks you to designate one code as primary. The rule of thumb is straightforward: your primary NAICS code should reflect the line of business that generates the largest share of your revenue. Not the work you find most interesting, not the market you hope to enter next year — the activity that actually brings in the most money today.

If you are a startup with no revenue history yet, pick the code for the activity you are organized to perform and expect to earn most from. You can change it later; nothing is carved in stone.

Step 3: Add secondary codes — selectively

Beyond the primary code, SAM.gov lets you list additional NAICS codes for other lines of business you genuinely operate in. These secondary codes matter mostly for visibility: when agencies, prime contractors, or small business specialists search registrant databases for vendors, they often filter by NAICS. If you do both custom software development and IT support services, list both.

Resist the temptation to add dozens of codes "just in case." A profile listing thirty loosely related codes signals to market researchers that you are not focused, and it does not expand what you can bid on. Which brings us to a crucial point many newcomers miss:

The codes in your SAM profile do not limit your bidding. Eligibility for a given solicitation is governed by the NAICS code the contracting officer assigned to that solicitation, not by what is in your registration. You can generally submit an offer under a code you never listed, provided you can perform the work and — for set-asides — meet the size standard for that code.

NAICS codes and SBA small business size standards

This is where your code choice has real teeth. The SBA assigns every NAICS code a size standard — the maximum size a business can be and still qualify as small for federal contracting purposes under that code. The full table is codified in federal regulation (13 CFR 121.201) and published on the SBA's website.

Size standards come in two flavors, depending on the industry:

Measure	Typical industries	How it is calculated
Average annual receipts	Most services, retail, construction, agriculture	Average of total receipts over the preceding five completed fiscal years
Number of employees	Most manufacturing, wholesale, some others	Average number of employees over the preceding 24 months

The thresholds vary enormously from one code to another, which is why choosing between two plausible codes is not always cosmetic. Under one code your firm might comfortably qualify as small and be eligible for set-aside contracts; under a neighboring code with a lower receipts threshold, it might not. When you complete the Representations and Certifications section of your SAM registration, you self-certify your size status against the standard for each NAICS code you list — so check the current SBA table for every code you add, and remember that what ultimately counts for any specific contract is the size standard of the code on that solicitation.

Note that socio-economic programs (8(a), HUBZone, women-owned, service-disabled veteran-owned) layer on top of this: all of them still require you to be small under the size standard of the relevant NAICS code.

Common mistakes to avoid

• Paying someone to register you. Worth saying a third time: SAM.gov registration is free. If a company implies it is affiliated with the government and demands a fee to register or "renew" you, walk away.
• Choosing an aspirational primary code. Your primary code should match where your revenue actually comes from, not the market you want to pivot into.
• Confusing NAICS with PSC. Federal contracting also uses Product Service Codes (PSC), which describe what is being bought rather than the seller's industry. They are a separate system; you may encounter both.
• Ignoring size standards when picking between similar codes. Two adjacent codes can carry very different SBA thresholds. Check before you commit.
• Using an outdated code. NAICS is revised every five years, and codes are occasionally split, merged, or renumbered. If you registered years ago, verify your codes still exist in the current edition — our NAICS lookup reflects the current code set.
• Letting the registration lapse. SAM registrations must be renewed every 365 days. An expired registration can make you ineligible for award, no matter how good your codes are.

Quick recap

1. Search for codes matching your real activities with a NAICS lookup tool or the Census Bureau's official pages.
2. Set as primary the code for the activity generating the most revenue.
3. Add a handful of secondary codes for other genuine lines of business.
4. Check the SBA size standard for each code before self-certifying as small.
5. Register and renew directly on sam.gov, for free, and review your codes at each annual renewal.

FAQ

Is SAM.gov registration free?

Yes. Registering an entity on SAM.gov, getting a Unique Entity ID (UEI), and updating your NAICS codes are all completely free. The official government site is sam.gov. If a website or a caller asks you to pay to register, renew, or "activate" your SAM record, be very cautious: many third parties charge for what the government provides at no cost, and some are outright scams.

Can I change my NAICS codes after registering on SAM.gov?

Yes. You can add, remove, or change your primary and secondary NAICS codes at any time by updating your entity registration on SAM.gov. Your registration must also be renewed every 365 days, which is a natural moment to review whether your codes still reflect what your business actually does.

Do the NAICS codes in my SAM.gov profile limit which contracts I can bid on?

No. The codes in your profile describe your business and help agencies find you, but eligibility for a specific solicitation is driven by the single NAICS code the contracting officer assigns to that solicitation and its associated SBA size standard. You can generally bid on opportunities under NAICS codes that are not listed in your SAM profile, as long as you can actually perform the work and meet the size standard when the contract is set aside for small business.

CodeClassify is an independent website and is not affiliated with, endorsed by, or connected to the U.S. government, SAM.gov, the U.S. Census Bureau, or the Small Business Administration. SAM.gov registration is free of charge on the official site, sam.gov. Information here is general guidance, not legal or contracting advice; always verify codes and size standards against the official SBA and Census sources before certifying anything in a federal registration.