- Construction NAICS codes split into three subsectors: 236 for building construction, 237 for heavy and civil engineering, and 238 for specialty trade contractors.
- Your primary NAICS code should match the largest share of your revenue, because it drives SBA size standards and set-aside eligibility in SAM.gov.
- Set-aside solicitations for SDVOSB, WOSB, 8(a), and HUBZone firms only go to businesses registered under the solicitation's NAICS code.
- Use the Census Bureau's free NAICS-to-SIC crosswalk when state forms or vendor databases still request retired SIC codes.
- Review your NAICS codes annually and before each SAM.gov renewal, updating the primary code when your revenue mix shifts.
Your NAICS code lookup for construction comes down to one decision: does your firm build structures (236), heavy civil work (237), or specialty trades (238)? Pick the code matching the majority of your revenue, because it determines which set-asides you qualify for and which solicitations appear in your searches. This guide walks through that choice step by step, including state-level variations and NAICS-to-SIC conversion.
How do I look up my construction NAICS code?
Run the lookup in three places: the Census NAICS search, your own revenue records, and SAM.gov. The Census tool is the authority, SAM.gov is where the code actually gets used, and your revenue decides which code you can defend.
Step 1: Start with the Census NAICS search
The US Census Bureau NAICS search tool lets you enter a keyword like "concrete" or "roofing" and returns matching 2022 codes with their definitions. Construction sits in sector 23, split into three subsectors: 236 (building construction), 237 (heavy and civil engineering), and 238 (specialty trade contractors). Read the definition under each candidate code, not just the title.
Step 2: Match the code to your revenue, not your ambition
Pick the code where the majority of your revenue actually comes from, based on receipts from your last completed fiscal year. If you did $180k of electrical work and $40k of general remodeling, you are a 238210 firm, not 236118. Your primary code drives size-standard limits and set-aside eligibility, so a code chosen to chase bigger jobs can disqualify you from the ones you could actually win. You can also run a keyword search on our NAICS code lookup page to shortlist candidates before you verify them in Census.
Step 3: Confirm in SAM.gov
Log into SAM.gov and check that your entity registration lists your chosen code as primary. If the code there does not match your revenue mix, update it before bidding on a set-aside solicitation, because agencies read that field to decide whether your bid belongs in the competition.
Why does my NAICS code matter for federal contracting?
Your primary NAICS code is not paperwork. It decides how big the government thinks you are, which set-asides you can win, and which solicitations ever reach you. Pick the wrong code and the right contracts stay invisible.
Size standards change by code
The SBA assigns each NAICS code a revenue or employee cap that defines "small." Heavy construction, specialty trade, and general building codes carry different dollar thresholds, so the same firm can be small under one code and other-than-small under another. If your registered code sets a cap you exceed, you are locked out of small-business set-asides in that code.
Set-asides filter on your code
A SDVOSB, WOSB, 8(a), or HUBZone set-aside is awarded only to firms registered under the solicitation's NAICS code in SAM.gov. Your certification helps only if your code matches the buyer's. Our guide to federal construction contracts in 2026 and 2027 shows how this matching drives the bid/no-bid call.
Wrong code, wrong opportunities
Opportunity feeds and market intel tools match solicitations to your codes. A miscoded firm sees a thin or misleading pipeline, then burns proposal hours on bids it was never eligible to win.
Which construction NAICS codes cover what? (236, 237, 238 explained)
Construction splits into three subsectors, and the one you pick changes your revenue size standard and which set-asides you fit. If you need the basics first, start with what a NAICS code actually is, then map your work below.
Sector 236: Building construction
236 covers structures people or businesses occupy: offices, schools, housing, retail. It splits into 2361 (residential building construction) and 2362 (nonresidential building construction). If you manage a build start to finish with your own crews and subs, this is your sector.
Sector 237: Heavy and civil engineering
237 is infrastructure: highways, bridges, utilities, water and sewer lines, site preparation. Think work funded by DOT or the Army Corps rather than a building owner.
Sector 238: Specialty trade contractors
238 is the trades: electrical, plumbing, HVAC, roofing, concrete, painting. Most first-time federal bidders with a single trade belong here.
| Sector | What it covers | Common codes | Size standard (avg. annual receipts) |
|---|---|---|---|
| 236 | Building construction | 236210, 236220 | Varies by code |
| 237 | Heavy and civil engineering | 237310, 237110 | Varies by code |
| 238 | Specialty trades | 238210, 238220 | Varies by code |
Check your exact revenue limit in the SBA size standards table (13 CFR 121.201), since limits differ by six-digit code.
How do I convert a NAICS code to a SIC code?
Why older systems still ask for SIC codes
SIC codes predate NAICS and were retired for federal statistical use in 1997, but some state registration systems, bonding forms, and private vendor databases still request them. If a form asks for SIC and you only know your NAICS, you need the crosswalk.
The official crosswalk, step by step
Use the free crosswalk maintained by the Census Bureau. Search your NAICS code (say, 236220), and the table returns the closest SIC match, often one code but sometimes several. For the reverse, a NAICS code lookup by SIC code, search the same table by SIC and read across. Confirm the NAICS result against the 2022 NAICS search tool so you are not working from an outdated scheme. Once your codes are locked in, they feed your SAM.gov profile and your capability statement, which shape how prime contractors find you for federal construction projects.
When the crosswalk is ambiguous
One NAICS code can map to multiple SIC codes because the two systems split industries differently. Construction is a common trouble spot: heavy and civil engineering work maps inconsistently. When several SIC codes appear, pick the one matching your dominant revenue activity, and note the ambiguity on the form if it allows comments.
Which NAICS codes apply to Ohio construction businesses?
Ohio does not issue its own NAICS codes. The state uses the same federal codes from the Census Bureau, so your NAICS lookup for construction works the same whether you are registering in SAM.gov or bidding an Ohio municipal job. What differs is how Ohio classifies you at the state level: the Ohio Secretary of State registers your business entity, and state prevailing-wage work on public improvements is tracked separately under Ohio labor law, not by NAICS.
Ohio state contractor registration
Ohio has no single statewide general contractor license. Registration happens at the entity level with the Secretary of State, and trade licensing (plumbing, electrical, HVAC) runs through local jurisdictions. Your NAICS code does not change with any of this.
Matching state work types to federal codes
Map the work you actually perform to the three-digit federal groups: 236 for new builds, 237 for heavy and civil, 238 for specialty trades. The Census NAICS-to-SIC crosswalk confirms these map cleanly to older SIC divisions, which some Ohio county procurement systems still reference. Once your codes are set, check how they filter into live solicitations on our construction contracts page.
Which NAICS codes apply to Virginia construction contractors?
Virginia's federal-heavy construction market
Virginia holds one of the densest federal construction footprints in the country. DoD, the Army Corps of Engineers, and the Navy drive a steady stream of solicitations through Norfolk, Hampton Roads, and Northern Virginia, alongside DC-area agency work spilling over the river. That mix means your NAICS code is doing double duty: it signals what you do to SAM.gov buyers and determines whether you qualify for set-asides those agencies reserve for SDVOSB, WOSB, 8(a), or HUBZone firms.
Codes that matter most for Virginia primes and subs
Naval and military facility work points to 236220 (Commercial and Institutional Building Construction) and 237990 (Other Heavy and Civil Engineering Construction) for site, utilities, and infrastructure scopes. Trade-level work, which is where many first-contract subs get their start, falls under 238210 (Electrical), 238220 (Plumbing and HVAC), and 238990 (All Other Specialty Trade Contractors). Match your primary code to the scope you can genuinely staff, because a Navy sources sought notice will filter respondents by it before anyone reads your capability statement.
Which NAICS codes apply to Delaware construction companies?
Delaware state procurement basics
Delaware buys construction through its own Office of Management and Budget rather than a single state portal, and local government work runs through municipal and county offices. For federal opportunities, your SAM.gov registration is still the gate: the NAICS codes you enter there determine which set-aside notices you can respond to. SAM.gov's entity registration help documentation walks through adding and editing NAICS codes on your registration, and you can list multiple codes with one designated as primary.
Common Delaware construction codes
Delaware's small geography means most firms span categories: 236220 (commercial and institutional building construction) for general contractors, 237310 (highway, street, and bridge construction) given the state's road-heavy infrastructure, and 238210 (electrical) or 238220 (plumbing) for trades. Pick the primary code that matches your largest revenue source, then add the rest so you appear in searches for both state and federal solicitations.
How do I pick one primary NAICS code when my firm does several things?
The revenue-share rule
Your primary code is the one matching the largest share of your revenue over the past three years, or your projected revenue if you are new. If you self-perform general construction (236220) and also do your own electrical work (238210), count the dollars, not the jobs. SAM.gov and set-aside eligibility both hang off this single code, so it has to reflect where the money actually comes from.
When secondary codes help (and when they dilute)
Add secondary codes for trades you genuinely perform in-house, not ones you subcontract out. Secondary codes let you prime on a wider range of solicitations and show up in more searches. They do not dilute eligibility, but listing codes you cannot back with past performance invites a bid/no-bid conversation you will lose.
Revisiting your codes as you grow
Revenue mix shifts. Review your NAICS list annually and before each SAM.gov renewal, and update your primary code when a different trade becomes your biggest line.
Frequently Asked Questions
Can I have more than one NAICS code in SAM.gov?
Yes. You designate one primary code, which drives set-aside eligibility and your size standard, then add secondary codes for trades you genuinely self-perform. Secondary codes widen the solicitations you can prime on and appear in more buyer searches. Skip codes for work you subcontract out.
What NAICS code should a handyman or small repair business use?
Most handyman and repair work falls under 238990, All Other Specialty Trade Contractors. If the majority of your receipts come from one specific trade, such as electrical (238210) or plumbing (238220), use that trade's code instead. Match the code to where your revenue actually comes from.
Does my NAICS code affect my SBA size standard?
Yes, directly. The SBA assigns each six-digit code a revenue or employee cap that defines small, and construction codes carry different thresholds. The same firm can be small under one code and other-than-small under another, so a miscoded registration can lock you out of set-asides.
How often should I update my NAICS codes?
Review them annually and before each SAM.gov renewal. Revenue mix shifts as you grow, and your primary code must match your largest revenue line. If a different trade becomes your biggest earner, update the primary code before bidding on any set-aside solicitation.
Is a NAICS code the same as a CAGE code?
No. A NAICS code classifies your industry; a CAGE code is a unique identifier assigned to your business entity for federal contracting. You need both in SAM.gov: the CAGE code tells agencies who you are, while your NAICS codes tell them what you do.