What is a NAICS code?
Updated November 10, 2026. Facts come from U.S. Census Bureau, SBA and GSA pages read on that date (listed under Sources). EasBid is an independent bid search service, not a government agency.
A NAICS code is a number of two to six digits that names a kind of business activity in the North American Industry Classification System, the standard federal statistical agencies use to classify businesses. In government contracting it does two jobs: it tells buyers what you do when you register in SAM.gov, and it tells you what a bid is for, because federal notices carry a NAICS code for the work. Look up yours with our free NAICS code lookup.
Where NAICS comes from
NAICS was developed under the U.S. Office of Management and Budget together with Statistics Canada and Mexico's national statistics institute, so that business statistics can be compared across the three countries. The Census Bureau maintains the U.S. version. It was first used in the United States in 1997 and the three countries agreed to review it every five years; the current edition is 2022 NAICS, which has 20 sectors and 1,012 industries in its U.S. version. It replaced the older SIC system.
The organizing idea is production: businesses that use similar processes to make their goods or deliver their services are grouped together. That is why "Roofing Contractors" sits with other specialty trade contractors in construction, while companies that sell roofing materials wholesale sit in wholesale trade.
How to read a NAICS code
The code is hierarchical. Each digit narrows the one before it:
| Digits | Level | Example |
|---|---|---|
| 23 | Sector | Construction |
| 238 | Subsector | Specialty Trade Contractors |
| 2381 | Industry group | Foundation, Structure, and Building Exterior Contractors |
| 23816 | NAICS industry | Roofing Contractors |
| 238160 | U.S. national industry | Roofing Contractors |
A zero in the sixth place usually means the U.S. industry is the same as the five-digit NAICS industry, as in the roofing example. Contracting uses the full six-digit code.
Common NAICS codes for contractors
These six-digit codes appear often on state, local and federal bids. Titles are from 2022 NAICS:
- 236220 Commercial and Institutional Building Construction
- 238160 Roofing Contractors
- 238210 Electrical Contractors and Other Wiring Installation Contractors
- 238220 Plumbing, Heating, and Air-Conditioning Contractors
- 238320 Painting and Wall Covering Contractors
- 237310 Highway, Street, and Bridge Construction
- 561720 Janitorial Services
- 561730 Landscaping Services
- 561612 Security Guards and Patrol Services
- 541511 Custom Computer Programming Services
- 541330 Engineering Services
- 541611 Administrative Management and General Management Consulting Services
Snow plowing has no code of its own; buyers usually tag it under landscaping or other building services, so read the scope as well as the code.
How to choose your NAICS codes
- Start from what you are paid for. List the products and services that bring in your revenue, then search each one in the lookup. Pick the six-digit code whose title and description match, not the closest-sounding word.
- Choose a primary code. SAM.gov asks you to mark one. It should be the activity that brings in the most revenue.
- Add the others you really do. Contracting officers and prime contractors search by code, so every honest match widens who can find you. Codes for work you do not do only add noise.
- Check the size standard for each. SBA assigns a size standard to every code, in employees or average annual receipts. You can be small under one code and not small under another.
- Read the codes on bids you want. If the notices you would bid on use a code you did not list, consider whether it fits and add it.
How NAICS codes are used in government bids
When you register in SAM.gov, the NAICS codes you list go into your entity record, and GSA notes that agencies often search by them to find businesses that can do the work. On the buying side, the contracting officer gives each solicitation one NAICS code that best describes the work. That code sets the size standard for the bid, so it decides whether a small business set-aside is open to you. Many state and local governments use other code sets (NIGP, UNSPSC or their own lists), so a state registration may ask for different codes; see our state vendor guides and state bid portals.
NAICS and small business size standards
SBA sets the size standards. As a general rule it says most manufacturing companies with 500 employees or fewer, and most non-manufacturers with average annual receipts under $7.5 million, qualify as small, but many industries have their own limits, listed in 13 CFR 121.201. SBA's size standards tool checks your figures against your codes. Because the solicitation's code sets the standard, the same firm can bid on a small business set-aside under one code and be too large under another.
NAICS, PSC, NIGP and UNSPSC: which code is which?
Four code sets show up in public bidding, and they answer different questions. NAICS describes the kind of business you are, and SAM.gov requires it. Product Service Codes (PSC) describe what the government is buying on a federal contract; SAM.gov lets you add them as an option, and GSA keeps the PSC manual on acquisition.gov. NIGP and UNSPSC are commodity code sets many states, cities and school districts use to send bid notices to registered vendors. You will often need two of them: NAICS for federal work and the state's own set for state work.
Finding open bids by NAICS code
Because each federal notice carries a NAICS code, searching by code is one of the quickest ways to find work that fits. On EasBid you can search by a two- to six-digit code (a shorter code matches everything under it, so 2382 finds roofing, electrical, plumbing and HVAC together), or open a code's own page from the lookup when it has open bids. A free alert then emails you once a week with new notices for that code.
Frequently asked questions
What is a NAICS code?
A NAICS code is a two- to six-digit number from the North American Industry Classification System that describes a type of business activity. Federal agencies use it to classify businesses, and buyers tag contract notices with the code for the work.
How many digits does a NAICS code have?
Up to six. The first two digits are the sector, the third the subsector, the fourth the industry group, the fifth the NAICS industry and the sixth the U.S. national industry.
Who assigns my NAICS code?
For contracting, you choose the codes that describe your work when you register in SAM.gov. The Census Bureau classifies establishments for statistics by their primary activity, but there is no official certificate of a NAICS code for a business.
Can a business have more than one NAICS code?
Yes. SAM.gov lets you list every code that matches your products and services, and you mark one as primary.
Which NAICS version is current?
The 2022 edition. NAICS is reviewed every five years; it was first used in the U.S. in 1997 and revised in 2002, 2007, 2012, 2017 and 2022.
What does NAICS have to do with being a small business?
SBA sets a small business size standard for each NAICS code, in employees or average annual receipts. A contract's NAICS code decides which size standard applies to that bid.
Sources
- North American Industry Classification System (U.S. Census Bureau) (census.gov, read November 10, 2026)
- 2022 NAICS Manual (U.S. Census Bureau) (census.gov, read November 10, 2026)
- Size standards (SBA) (sba.gov, read November 10, 2026)
- Get started with contracting (SBA) (sba.gov, read November 10, 2026)
- Register your business (GSA) (gsa.gov, read November 10, 2026)
- Entity Registration Checklist (GSA, on SAM.gov) (sam.gov, read November 10, 2026)