Every federal contract solicitation lists a NAICS code. That code determines whether you qualify as a small business for that award, which set-aside programs apply, and whether you can even compete. Getting your NAICS codes right in SAM.gov is one of the first real decisions you make as a federal contractor.
What NAICS codes are
NAICS stands for North American Industry Classification System. The federal government uses 6-digit codes to classify every business and every contract by industry. The Census Bureau publishes the full list; the current version is NAICS 2022.
The structure is hierarchical. The first two digits are the sector (54 is Professional, Scientific, and Technical Services). Add digits and you get more specific: 541611 is Administrative Management and General Management Consulting Services. That 6-digit code is what shows up on a solicitation, what you list in SAM.gov, and what the SBA uses to determine your size standard.
There are roughly 1,000 6-digit NAICS codes in active use across federal procurement. Most small businesses need between three and six of them.
How to find the right NAICS codes for your business
Start with three sources:
1. NAICS.com keyword search. Go to naics.com and search plain-English descriptions of what your business does. Type "cybersecurity" or "janitorial services" or "civil engineering." The site returns matching codes with descriptions. It's faster than reading the Census Bureau's official manual, and the descriptions are clearer.
2. SBA's NAICS lookup tool. The SBA maintains a size standards tool at sba.gov/size-standards. You enter a NAICS code and it returns the current size threshold — either annual receipts (in millions) or number of employees, depending on the industry. Use this to cross-check every code you're considering.
3. FPDS and beta.SAM.gov historical awards. The Federal Procurement Data System (FPDS) tracks every federal contract. Go to sam.gov/data-services/Award-Notices or use beta.SAM.gov's award search, filter by NAICS code, and see what agencies are actually buying under that code and at what dollar values. This tells you whether there's real demand for your NAICS code in federal procurement — not just whether the description matches your work.
Search tip: on beta.SAM.gov, use the "Contract Opportunities" search. Filter by NAICS code, then add an agency filter. You'll see active solicitations and historical awards. If a code you're considering returns zero results for your target agency over the past two years, that's a signal the agency doesn't buy under that code, even if the description fits your business.
Primary NAICS vs. additional NAICS in SAM.gov
When you register in SAM.gov, you enter a primary NAICS code and can add additional codes. The primary code is the one the SBA uses if there's ever a size protest, and it's the one most visible to contracting officers reviewing your profile. Make it your highest-revenue or most strategically important code.
List three to five codes total. Listing twenty codes signals to contracting officers that you'll bid on anything, which is rarely a selling point. More important: every code you list should reflect actual work you do or are equipped to do. If you're ever asked to justify your NAICS selection during a size determination, you need to back it up.
Some businesses legitimately span multiple codes. An IT firm might carry 541511 (Custom Computer Programming Services), 541512 (Computer Systems Design Services), and 541519 (Other Computer Related Services). A construction firm might list several codes under sector 23. That's appropriate. What to avoid: listing manufacturing codes if you're a services firm, or listing highly specialized research codes if you don't have the credentials to support them.
Small business size standards by NAICS
Every NAICS code has a size standard set by the SBA. Exceed it and you're no longer a small business for that code — which means you're not eligible for small business set-asides under that NAICS.
Size standards come in two forms:
Revenue-based: Most service industries use annual average receipts over three years. Common thresholds range from $8 million (some janitorial and landscaping codes) to $47 million (some engineering codes) to $34 million (many IT services codes). A few go higher.
Employee-based: Manufacturing and mining NAICS codes typically use employee count, commonly 500 or 750 employees, sometimes 1,500 for certain sectors.
The SBA publishes the full table at sba.gov/size-standards. It's updated periodically — the most recent major revision was in 2022. Always verify the current threshold before certifying your size status in SAM.gov. If you're near the threshold, get your accountant involved. The three-year averaging calculation has nuances.
One mistake to avoid: assuming your small business status under your primary NAICS applies to all your codes. Each code has its own standard. You could be small under 541611 and large under 541519 if the thresholds differ and your revenue is near the line.
Why NAICS code selection matters for set-asides
This is where NAICS selection has the most direct business impact.
WOSB set-asides are NAICS-specific. The Women-Owned Small Business (WOSB) Federal Contract Program only authorizes set-asides in industries where women-owned businesses are "underrepresented" or "substantially underrepresented." The SBA maintains the list. As of the most recent update, roughly 700 NAICS codes qualify. If your primary NAICS isn't on the list, agencies cannot set aside contracts for WOSBs under that code. You can still compete on full-and-open contracts, but the set-aside authority doesn't apply.
EDWOSB (Economically Disadvantaged WOSB) set-asides are limited to the "substantially underrepresented" subset, an even shorter list.
Check the current WOSB eligible NAICS list at sba.gov/federal-contracting/contracting-assistance-programs/women-owned-small-business-federal-contract-program before you finalize your SAM.gov registration.
8(a) and HUBZone set-asides are not NAICS-restricted in the same way — those programs cover all industries — but the solicitation will still list a NAICS code that determines your size standard for that specific award. If a HUBZone set-aside is awarded under a manufacturing NAICS with a 500-employee threshold, a 250-employee manufacturer qualifies; a 600-employee manufacturer does not.
SDVOSB and VOSB set-asides through the VA use NAICS codes to determine small business size the same way. No NAICS restrictions on eligible industries, but you need to be small under the specific code on the solicitation.
How to research which NAICS codes a target agency buys under
Don't guess. Look at the data.
Go to beta.SAM.gov. Under "Contract Awards," enter the agency name (try both the department level and the sub-agency, e.g., "Department of Defense" vs. "Army Corps of Engineers"). Then add a NAICS code filter for each code you're considering.
What you're looking for: how many awards the agency made under that code in the past two fiscal years, the dollar range of those awards, and whether they were set-asides or full-and-open. If an agency you're targeting made 40 awards under NAICS 541611 last year, 30 of which were small business set-asides, that's a strong signal to include 541611 in your SAM.gov profile.
USASpending.gov offers another angle. Search by agency and filter by NAICS to see total obligated dollars. This is useful for sizing the opportunity — how much money flows through a given code at a given agency.
FPDS-NG (the legacy system at fpds.gov) still works and has detailed contract-level data. It's less user-friendly than beta.SAM.gov but useful for pulling bulk data on a specific code.
Top NAICS codes for diverse service businesses
These codes appear frequently in small business set-aside awards and are common among WOSB, 8(a), and SDVOSB firms:
| NAICS | Description | Size Standard |
|---|---|---|
| 541611 | Administrative Mgmt & General Mgmt Consulting | $24.5M |
| 541612 | Human Resources Consulting | $24.5M |
| 541690 | Other Scientific & Technical Consulting | $19M |
| 541715 | R&D in Physical, Engineering, and Life Sciences | 1,000 employees |
| 541990 | All Other Professional, Scientific & Technical Services | $19M |
| 561110 | Office Administrative Services | $12.5M |
| 561210 | Facilities Support Services | $47M |
| 611430 | Professional & Management Development Training | $12.5M |
| 541519 | Other Computer Related Services | $34M |
| 541512 | Computer Systems Design Services | $34M |
The IT codes (541511, 541512, 541519) appear across nearly every federal agency. Training and HR codes (561110, 611430, 541612) are common at civilian agencies and the VA. If you do facilities or environmental work, codes in sectors 56 and 562 see heavy set-aside activity at DoD installations.
Before you finalize your SAM.gov profile
Run your proposed NAICS list through three checks. First, confirm your size status under each code using the current SBA table. Second, if you hold or plan to pursue a WOSB or EDWOSB certification, verify each code against the SBA's eligible NAICS list. Third, search beta.SAM.gov for active solicitations and recent awards under each code at your target agencies. If the data supports the code, keep it. If there's no procurement activity, drop it and use the space for a code with real demand.
Your NAICS codes are not permanent. You can update your SAM.gov registration at any time. As your business evolves or as you win work in new areas, update accordingly. The registration is annual anyway — treat the NAICS review as part of your annual renewal process.
