Every solicitation needs one. Pick the wrong one and you'll hear about it. Here's how to get it right.
NAICS selection isn't glamorous, but it directly affects who can compete for your contract. Get it wrong and you'll limit competition or face a protest.
NAICS stands for the North American Industry Classification System. It's a six-digit code that classifies every business establishment by its primary activity. Think of it as the government's way of saying "this contract is for this kind of work."
Every solicitation you issue must include a NAICS code. It tells industry what you're buying and, critically, it determines the size standard — the threshold that decides whether a company qualifies as a small business for that particular contract.
Three reasons, and they all affect you directly:
Here's the practitioner framework. Two rules:
Rule 1: Pick the code that most accurately reflects the requirement. What is the principal purpose of the acquisition? If you're buying janitorial services, don't use a general "facilities support" NAICS just because it's broader. Use the janitorial code.
Rule 2: When two codes fit equally well, pick the one that invites more competition. More competition = better prices, more options, and a stronger defense if someone challenges your choice.
For services: NAICS codes for services span a wide range. Focus on what the contractor will actually do. IT services, janitorial, engineering, consulting — each has its own series. Search by the function, not by who you think should do the work.
For construction: You're in the 23 series. Construction NAICS codes are broken down by type (general, heavy/civil, specialty trades). Match the code to the type of construction work being performed.
Every NAICS code has a corresponding SBA size standard — either a revenue cap (e.g., $16.5M in average annual receipts) or an employee count (e.g., 500 employees). This size standard determines the small business threshold for contracts assigned that NAICS code.
This is why NAICS selection matters beyond just classification. If you assign a NAICS code with a $9M size standard instead of one with a $30M standard, you've just changed which companies can compete as "small." Think about that when you're deciding between two codes that both seem to fit.
Before you finalize your NAICS selection, you should know what NAICS codes your potential offerors actually claim. Here's how:
Go to SAM.gov and search for the company. In their entity registration, look for their Representations and Certifications. Under the provision 52.219-1 (Small Business Program Representations), you'll find the NAICS codes they've registered under and whether they represent themselves as small for each one.
Answer one question and get tailored guidance for selecting the right NAICS code.
Select the category that best describes the principal purpose of your acquisition.
For supplies, your first stop should be the Manufacturing sector:
Search for the code that describes what the product is, not who sells it. For example, if you're buying ammunition, look for the specific manufacturing code (e.g., 332992 — Small Arms Ammunition Manufacturing), not a general retail or wholesale code.
Why manufacturing codes? Using a manufacturing NAICS for supply contracts keeps things cleaner under the Non-Manufacturer Rule (FAR 19.108). This rule requires small business offerors on supply contracts to provide the product of a small business manufacturer. Selecting the manufacturing NAICS aligns your solicitation with this requirement from the start.
Services span a wide range of NAICS series. The key is to focus on what the contractor will actually do.
Common service NAICS series:
Don't default to a catch-all. "Administrative Management and General Management Consulting" (541611) is a popular pick, but if your requirement is really for IT help desk support, the right answer is probably in the 541500 range. Be specific to the work being performed.
If two codes seem to fit, apply the tiebreaker: pick the one that invites more competition.
Construction work lives in one place:
The 23 series breaks down into three main areas:
236 — Construction of Buildings (residential and nonresidential building construction)
237 — Heavy and Civil Engineering (highways, bridges, utilities, power lines)
238 — Specialty Trade Contractors (electrical, plumbing, HVAC, roofing, concrete, etc.)
Match the code to the type of construction work being performed. If it's a renovation of an office building, that's 236. If it's re-roofing, that's more likely 238160 (Roofing Contractors).
Seven scenarios. Pick the best answer. See if the training stuck.
Use these tools to search for NAICS codes and verify size standards.
Search NAICS codes by keyword or industry description. Find the six-digit code that matches your requirement.
Search on NAICS.comThe official table of size standards. Look up any NAICS code to see its small business revenue cap or employee threshold.
SBA Size Standards TableThe official source for NAICS code definitions, hierarchies, and crosswalks. Useful when you need the precise scope of a code.
Census.gov NAICSNeed to map between the older SIC system and NAICS? The Census Bureau maintains the official crosswalk.
NAICS-SIC CrosswalkThe Non-Manufacturer Rule. Read the actual regulation that drives the preference for manufacturing NAICS codes on supply contracts.
Read FAR 19.108Another solid keyword search tool for NAICS codes. Cross-reference with NAICS.com if you're not sure about a code.
NAICS Code DescriptionsLook up a company's NAICS codes and small business representations. Find their 52.219-1 reps & certs to see which NAICS codes they claim and their size status under each.
Search SAM.gov