NAICS codes are the six-digit industry codes that determine which government contracts you can compete for and whether you qualify as a small business. Choosing them well is one of the most important setup decisions a federal contractor makes. This guide explains what NAICS codes are, how to find yours, and the codes that matter most in government contracting.
What is a NAICS code?
NAICS (North American Industry Classification System) is the standard the federal government uses to classify businesses by industry. Every federal solicitation is tagged with one NAICS code, and each code carries an SBA size standard that defines who counts as a small business for that opportunity. You can hold many codes but designate one primary code in SAM.gov.
How to find your NAICS code
Search the official NAICS code list at census.gov by keyword (for example, "electrical" or "consulting"), or browse by sector. Pick every code that genuinely describes your work, then choose the one that best represents your core business as your primary code.
Common NAICS codes for construction and contractors
- 236220 — Commercial & Institutional Building Construction (SBA size standard $45.0M)
- 237310 — Highway, Street & Bridge Construction ($45.0M)
- 238210 — Electrical Contractors & Other Wiring ($19.0M)
- 238220 — Plumbing, Heating & Air-Conditioning ($19.0M)
- 238990 — All Other Specialty Trade Contractors ($19.0M)
- 541330 — Engineering Services ($25.5M)
- 541512 — Computer Systems Design Services ($34.0M)
Need the deep dive for the trades? See our dedicated guide to NAICS codes for construction & contractors.
How NAICS codes set your small-business status
Each NAICS code has its own SBA size standard, expressed as average annual receipts or number of employees. You are "small" only relative to the size standard of the solicitation’s NAICS code—so the same firm can be small for one contract and not for another. Learn how this works in our SBA size standards guide.
NAICS codes and your GSA Schedule
Your NAICS codes map to the Large Categories and Special Item Numbers on the GSA Multiple Award Schedule, and they drive which opportunities you see when you search for government contracts.
Frequently asked questions
Where can I find the NAICS code list?
The official, searchable NAICS code list is published by the U.S. Census Bureau at census.gov and is updated every five years.
Can my business have more than one NAICS code?
Yes—there is no limit. List every code that fits your work and designate one as primary in SAM.gov.
What is the NAICS code for a general contractor?
General building contractors typically use 236220 (commercial) or 236118 (residential remodeling).
Not sure which codes and SINs fit your business? Book a free discovery call. — Reviewed by the GSA Focus team.
