# What Is a NAICS Code for Construction?
You started a SAM.gov registration, hit a field asking for your NAICS codes, and stopped. Pick the wrong ones and the right solicitations never reach you. A NAICS code for construction is the six-digit number the federal government uses to classify what your business actually does, and it quietly controls which contracts you see, which small business size standard applies to you, and whether you are eligible to bid at all.
The short answer
NAICS stands for the North American Industry Classification System. Each six-digit code describes one industry, and construction sits in sector 23. Every federal solicitation is assigned one NAICS code by the contracting officer, and that code carries a small business size standard — a revenue or employee ceiling. If your registered codes do not match the solicitation, you will not surface in searches and you may not qualify as a small business for that award.
Key Takeaways
- Construction is sector 23; the specific six-digit code is what matters for bidding.
- Every solicitation has exactly one assigned NAICS code, chosen by the contracting officer.
- Each code carries its own small business size standard, usually stated in annual receipts.
- You can and should register multiple codes that genuinely describe your work.
- Registering codes you cannot perform is a real compliance problem, not a shortcut.
How the numbering works
The six digits narrow from broad to specific. Sector 23 is Construction. Within it, 236 covers construction of buildings, 237 covers heavy and civil engineering construction, and 238 covers specialty trade contractors. The last digits get specific from there.
A roofing contractor, for example, falls under specialty trade contracting rather than building construction — which matters, because the size standard attached to those codes is not the same. Two companies of identical revenue can be small under one code and not small under another.
Common construction NAICS codes
| Code | What it covers | Typical bidder |
|---|---|---|
| 236220 | Commercial and institutional building construction | General contractors on federal buildings |
| 237310 | Highway, street and bridge construction | Heavy civil contractors |
| 238160 | Roofing contractors | Roofing specialty firms |
| 238210 | Electrical contractors | Electrical subcontractors |
| 238220 | Plumbing, heating and air-conditioning contractors | Mechanical subcontractors |
| 238910 | Site preparation contractors | Excavation and demolition firms |
This is a starting point, not the full list. The official listing is maintained by the Census Bureau, and the full NAICS reference is published and searchable there.
Why the size standard is the part that bites
Attached to every NAICS code is a small business size standard set by the Small Business Administration — normally a three-year average annual receipts figure for construction codes. If your average receipts are below the standard for the code on that solicitation, you can compete for small business set-asides under it.
Here is what surprises people: because standards differ by code, your small business status is not one fact about your company. It is a fact about your company relative to a particular solicitation. Growing companies often stay small under one code while ageing out under another, and that is normal rather than a mistake.
The SBA publishes the current size standards table, and it is worth checking the specific code before you invest time in a bid.
Choosing your codes without guessing
Three practical rules.
Register what you actually perform. The list should describe work you can self-perform or manage with a real team. Registering everything in sector 23 to catch more searches is a well-known and easily spotted pattern, and it creates a genuine problem if you win something you cannot deliver.
Look at contracts you want, not just work you have done. Search past awards in the type of work you are targeting and note which codes those solicitations carried. That tells you what to register far better than a self-assessment does.
Put your primary code first. Your primary NAICS is what most people see first when they look you up, and it should be the work you most want to be found for.
Where the code shows up in the process
You choose codes during SAM.gov registration and they stay attached to your entity record. From then on, they filter what you find and how you are found. If you have not been through that process yet, our step-by-step on how to register on SAM.gov for federal contracts covers the sequence and the documents you will need in front of you.
When you start reading solicitations, the assigned NAICS is stated near the top along with the set-aside type. Checking that one field first saves hours: if your company is not small under that code, the rest of the document does not matter for you.
The mistake that costs the most time
Bidding on a solicitation whose NAICS code you are not registered for, or not small under, and finding out at evaluation. It is not a technicality that gets waived. Contracting officers use it as a threshold question.
The fix takes ten minutes. Before you invest in a bid, confirm the code on the solicitation, confirm your registration includes it, and confirm your three-year average receipts sit under the standard for that code.
If you are earlier than that in the process, how to win government construction contracts is the wider walkthrough, and winning a contract without prior federal experience covers the past-performance problem most new bidders hit next.
Get the codes right before you spend time bidding
Federal Construction University teaches contractors how to find, qualify for and win federal construction work — from registration and code selection through bidding and administration.
Book a complimentary 30-minute consult with a business owner who has won millions in government contracts, and bring the codes you are considering. It is a much cheaper conversation than a disqualified bid.
Frequently Asked Questions
What NAICS code is used for roofing contractors?
Roofing contractors fall under 238160, within the specialty trade contractor group rather than building construction. That distinction matters because the small business size standard attached to specialty trade codes differs from the standard on building construction codes.
Can I register more than one NAICS code?
Yes, and you should register every code that genuinely describes work you can perform or manage. What you should not do is register broadly to appear in more searches, because winning work you cannot deliver is a real compliance problem.
How do I find the right NAICS code?
Search past awards for the kind of work you want and note which codes those solicitations carried. That reflects how contracting officers actually classify the work far better than reading definitions and self-assessing.
What is a small business size standard?
It is the ceiling, set by the Small Business Administration, below which a company counts as small for a given NAICS code. For construction codes it is normally stated as a three-year average of annual receipts.
Can I be small under one code and not another?
Yes, and that is common. Size standards vary by code, so small business status is a fact about your company relative to a particular solicitation rather than a single permanent status.
Where is the official NAICS list published?
The Census Bureau maintains and publishes the official NAICS listing, and it is searchable free of charge. Size standards for each code are published separately by the Small Business Administration.
