NAICS Codes for Government Contracting
A working guide for federal contractors. What NAICS codes are, why they matter for SAM.gov + set-asides, how to find yours, and the common mistakes that cost contracts.
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What a NAICS code is
NAICS (the North American Industry Classification System) is the federal standard for sorting businesses by their primary economic activity. Every federal contract carries at least one NAICS code. Every contractor registered in SAM.gov picks one primary NAICS and up to 29 secondaries.
The system is hierarchical:
- Sector (2 digits) — 20 high-level industries (e.g. 54 is “Professional, Scientific, and Technical Services”)
- Subsector (3 digits) — narrower groupings within a sector
- Industry group (4 digits) — closely related industries
- NAICS industry (5 digits) — finer breakdown
- National industry (6 digits) — the specific code used in procurement
When a solicitation cites NAICS 541512, it means “Computer Systems Design Services” — a 6-digit national industry. The same record rolls up to subsector 5415 (Computer Systems Design and Related Services), then to sector 54.
Why NAICS matters for government contracting
Three load-bearing reasons:
- Eligibility. Solicitations are tagged with one NAICS. Only contractors registered under that NAICS (primary or secondary) can bid.
- Small business size. The SBA Table of Size Standards sets a revenue or employee cap per NAICS. A business that's “small” under one code can be “other than small” under another. The size standard determines whether you qualify for set-asides on that contract.
- Past performance + capability statement. Contracting officers screen submissions by NAICS. Registering under codes you can't deliver against weakens your past-performance record on the codes you can.
How to find the right NAICS code for your business
The working approach:
- Write down what your business actually delivers — in customer language, not marketing copy.
- Search the Bureauify NAICS Code Explorer for keywords matching that delivery. Each result links to the detail page with real federal contract counts under that code.
- Cross-check against the official Census Bureau NAICS lookup — this is the authoritative source.
- Check the SBA size standard for each candidate code. Pick the code where (a) you can credibly perform, AND (b) the size standard leaves you eligible for small-business status if that matters for your strategy.
- Designate the code with your highest revenue concentration as your primary. List the rest as secondaries (up to 29).
The 20 NAICS sectors
Every 6-digit code rolls up to one of these. Sector 54 (Professional, Scientific, and Technical Services) captures the largest share of federal contract dollars — the 541-series is where IT, engineering, and consulting contracts live.
- 11Agriculture, Forestry, Fishing and Hunting
- 21Mining, Quarrying, and Oil and Gas Extraction
- 22Utilities
- 23Construction
- 31-33Manufacturing
- 42Wholesale Trade
- 44-45Retail Trade
- 48-49Transportation and Warehousing
- 51Information
- 52Finance and Insurance
- 53Real Estate and Rental and Leasing
- 54Professional, Scientific, and Technical Services
- 55Management of Companies and Enterprises
- 56Administrative and Support and Waste Management
- 61Educational Services
- 62Health Care and Social Assistance
- 71Arts, Entertainment, and Recreation
- 72Accommodation and Food Services
- 81Other Services (except Public Administration)
- 92Public Administration
Common NAICS mistakes that cost contracts
- Registering too broadly.30 NAICS codes do not make you bid-eligible on more contracts in any useful sense. Contracting officers don't reward breadth — they reward credibility on the specific code in the solicitation. Past performance dilutes when spread thin.
- Picking the wrong primary.Your primary NAICS drives most of SAM.gov's default filtering and most of your outbound capability statements. If your primary doesn't match your highest revenue line, you're leaving search-visibility on the table.
- Ignoring size-standard math.A business that's “small” under one code can be priced out as “other than small” under another. This kills set-aside eligibility silently — you never see the contract opportunity because the solicitation never surfaces.
- Forgetting to update after NAICS revisions. NAICS is revised every 5 years. SAM.gov auto-migrates, but agencies sometimes lag. If your capability statement still references a retired code, it ages poorly.
Next steps
- Browse all 1,051 NAICS codes with real federal contract counts.
- Read the SAM.gov registration guide for the full registration workflow.
- See the set-aside programs tied to specific NAICS codes (8(a), SDVOSB, WOSB, HUBZone).
- Search live federal opportunities by NAICS at the opportunities page.
Frequently asked questions
What is a NAICS code?
NAICS (North American Industry Classification System) is the standard the U.S. government uses to classify business establishments by their primary economic activity. Every federal contract is tagged with at least one NAICS code, and every contractor must register with the NAICS codes that match what their business actually does. There are 1,051 detailed 6-digit codes grouped under 20 high-level sectors (codes 11 through 92).
Why do NAICS codes matter for government contracting?
NAICS codes drive three things: (1) which contracts you can compete for — solicitations are restricted to specific NAICS classifications, (2) which size standard applies to your small-business status (revenue caps and employee counts vary by code), and (3) which set-aside programs you qualify for. Picking the wrong primary NAICS in SAM.gov can disqualify you from contracts that should otherwise be a fit.
How do I find the right NAICS code for my business?
Start by describing what your business actually delivers in plain language, then search the Bureauify NAICS Code Explorer or the official Census NAICS lookup. Most businesses use multiple NAICS codes — designate the one with the highest revenue share as your primary. The SBA size standards table tells you which codes give you small-business eligibility based on either annual revenue (~$16.5M–$41.5M typical caps) or employee count (~500–1,500 typical caps).
How many NAICS codes can I register on SAM.gov?
SAM.gov allows up to 30 NAICS codes per entity registration, but having more does not necessarily help — contracting officers search by code, not by quantity. The right strategy is to register every code where you can credibly perform AND where the size standard works in your favor. Adding codes you cannot actually deliver against can hurt your past-performance scoring on competitive bids.
What is the difference between primary and secondary NAICS?
Your primary NAICS is the single code that represents your principal line of business — typically the one with the highest revenue concentration. SAM.gov requires exactly one primary. Secondary NAICS codes (up to 29 more) cover adjacent capabilities. Solicitations are tagged with a specific NAICS, and contractors registered under that code (primary or secondary) are eligible to bid.
Are NAICS codes updated?
Yes — NAICS is revised every five years by the Office of Management and Budget. The current edition is NAICS 2022 (in use through 2027). Major revisions create new codes, retire obsolete ones, and reorganize sectors. SAM.gov updates automatically, but agencies sometimes lag — contracts may still reference NAICS 2017 codes for several years after a revision. Bureauify normalizes both editions in its search index.
What is a NAICS size standard?
A NAICS size standard is the threshold below which a business qualifies as "small" for federal contracting under that specific code. The SBA publishes the official table. Size standards come in two flavors: revenue-based (annual receipts over the trailing 5 years must be at or below the cap) or employee-based (average employees over the trailing 12 months must be at or below the cap). The cap varies dramatically by code — from $7M for some retail codes to $46M+ for several construction codes, or from 500 employees to 1,500 for manufacturing.
Which NAICS codes get the most federal contracts?
The 541-series (Professional, Scientific, and Technical Services) consistently captures the largest share of federal contract dollars, followed by 336 (Transportation Equipment Manufacturing — heavy in defense), 237 (Heavy Construction), and 334 (Computer and Electronic Product Manufacturing). Specific high-volume codes include 541330 (Engineering Services), 541512 (Computer Systems Design), 541611 (Management Consulting), and 541715 (R&D in the Physical Sciences). Use the Bureauify NAICS pages to see real award counts by code.