NAICS Codes and SBA Size Standards: How to Know If You Count as Small
How NAICS codes and SBA size standards decide whether you can bid a federal small business set-aside, when size is measured, and how to check it.
Every federal small business set-aside asks the same quiet question before it ever looks at your price or your technical approach: are you actually small for this contract? The answer is not a feeling about your company, and it is not one fixed label you earn once. It depends on the North American Industry Classification System (NAICS) code the contracting officer assigned to that specific solicitation, and on the size standard the Small Business Administration (SBA) ties to that code. This article explains how those two pieces fit together, when your size is measured, what you represent in SAM.gov, what happens if someone challenges you, and how to check your status before you spend a week writing a proposal.
What a NAICS code is and why the government uses it
NAICS is the standard system for classifying businesses by the product or service they provide. SBA's get started with contracting guide explains that NAICS codes classify businesses based on the particular product or service they supply, that a business generally has a primary NAICS code, and that it can have several codes if it sells several kinds of products and services. SBA points businesses to the U.S. Census Bureau's NAICS list to find their codes.
In federal contracting, a NAICS code does two jobs at once. It describes what the government is buying, and it unlocks the size standard used to decide who can compete as a small business. Under FAR 19.102(a), SBA establishes small business size standards on an industry-by-industry basis, and those size standards and their corresponding NAICS codes are published at 13 CFR 121.201 and in SBA's table of size standards. The same section notes that NAICS codes are updated by the Office of Management and Budget every five years, and that new NAICS codes cannot be used in federal contracting until SBA publishes corresponding size standards.
That means your company does not have one size. You can be small under one NAICS code and other than small under another, because each code carries its own ceiling. A firm with a few dozen employees and modest revenue will usually be small almost everywhere, but a growing firm near a threshold has to check code by code.
How size standards are measured
SBA's guidance describes size standards as the maximum size that a business, together with its affiliates, can be to qualify as small for a particular contract. Some standards are expressed in number of employees and others in average annual receipts, depending on the industry. SBA's own summary is that most manufacturing companies with 500 employees or fewer, and most non-manufacturing businesses with average annual receipts under $7.5 million, will qualify as small, but that there are exceptions by industry. Do not rely on that rule of thumb for a real bid. Look up the exact standard for the exact code in SBA's table of small business size standards or in 13 CFR 121.201, or use SBA's size standards tool.
The words "and its affiliates" matter more than many first-time bidders expect. Size is not measured for your company alone if other businesses control it, are controlled by it, or share common ownership or management with it under SBA's affiliation rules in 13 CFR part 121. If you or your co-owners hold stakes in other companies, read those rules or talk to an SBA resource partner before you represent that you are small. A size protest that turns on affiliation can cost you an award you otherwise won.
The contracting officer picks one code per solicitation
You do not choose the NAICS code for a set-aside; the agency does. FAR 19.102(b)(1) says contracting officers shall assign one NAICS code and corresponding size standard to all solicitations, contracts, and task and delivery orders, except for certain multiple-award contracts. The contracting officer picks the one industry that best describes the principal purpose of the supply or service being acquired, giving primary consideration to the NAICS Manual's industry descriptions, the product or service descriptions in the solicitation, the relative value and importance of the components of the requirement, and the function of what is being purchased. A procurement is usually classified according to the component that accounts for the greatest percentage of contract value.
Multiple-award contracts are changing. Under FAR 19.102(b)(2), solicitations for multiple-award contracts issued on or before October 1, 2028 follow the single-code rule, while those issued after that date must either use a single code that fits both the contract and each order, or split the work into distinct portions such as line items or Special Item Numbers with one code each. If you bid on more than one portion, FAR 19.301-1(a) requires you to meet the size standard for each portion you offer on.
The size standard that applies is the one in effect on the date the solicitation is issued, under FAR 19.102(c). If SBA changes the standard and the change takes effect before initial offers are due, the contracting officer may amend the solicitation to use the new standard. So when you read a notice, the NAICS code and size standard printed on it are the ones to test yourself against, not whatever code you listed first in your own registration.
Hypothetical example: a small firm that does both janitorial work and minor building repairs sees a notice for custodial services at a federal office building that includes a small amount of repair work. The contracting officer would normally assign the code that matches the principal purpose and the largest share of value, which here is the custodial work. The firm should check its size against the janitorial size standard on the notice, even if most of its own revenue comes from repairs.
When your size is measured
Timing is one of the most misunderstood parts of size. Under FAR 19.102(a)(3), SBA determines the size status of a concern, including its affiliates, as of the date the concern represents that it is small to the contracting officer as part of its initial offer, which includes price. FAR 19.301-1(b) adds that an offeror must represent its size and socioeconomic status in writing to the contracting officer at the time of initial offer. For multiple-award contracts that do not require price in the initial offer, FAR 19.102(a)(4) says size is still measured as of the date of the initial offer for the contract.
In practical terms, the snapshot is taken when you submit. If your firm is small on the day you send your initial offer, later growth during evaluation does not by itself change that snapshot for that procurement. The reverse is also true: if you are already over the standard on the day you submit, a promise that you will shrink does not help. HUBZone has its own timing rule, too; FAR 19.301-1(d) requires a HUBZone small business to be a HUBZone small business concern at the time of initial offer.
What you represent in SAM.gov and on each offer
Most of your size representations live in your SAM.gov registration. FAR 4.1201 requires offerors to complete electronic annual representations and certifications in SAM.gov as part of required registration, and to review and update them as necessary, but at least annually, to keep them current, accurate and complete. That is where you list the NAICS codes you work in and represent your size against them. SBA's guide describes your SAM profile as something like a resume that contracting officials search, so listing every code you genuinely perform in helps you show up when they do market research.
Under FAR 19.301-1(a), to be eligible for award as a small business, an offeror must represent in good faith that it meets the size standard for the NAICS code in the solicitation and that SBA has not issued a written determination saying otherwise. The contracting officer generally accepts that representation under FAR 19.301-1(f) unless another offeror or interested party challenges it or the contracting officer has a reason to question it. A representation is not binding on SBA, which makes the final call if your size is challenged.
If you are new and still registering, our SAM.gov registration step-by-step guide walks through the entity registration, and what is a small business set-aside covers the basics of how set-asides work once you are registered.
Size protests: what happens if a competitor says you are not small
Other bidders can challenge you. FAR 19.302 allows an offeror, the contracting officer, SBA or another interested party to protest the small business representation of an offeror in a specific offer, with narrower standing rules for competitive 8(a) contracts. The protest must be in writing, must give specific, detailed evidence that the offeror is not small, and is dismissed by SBA if it lacks specific grounds. To affect a particular solicitation, a protest from a competitor generally must reach the contracting officer by close of business on the fifth business day after bid opening, or after the notice identifying the apparently successful offeror in a negotiated buy.
The lesson for a new bidder is simple. Represent your size honestly, keep records of your employee counts or receipts and any ownership ties to other companies, and assume a losing competitor may look closely if you win.
You can appeal a NAICS code you think is wrong
Sometimes the code on a notice looks wrong for the work described, and the choice can decide whether your firm is eligible at all. Under FAR 19.103, the contracting officer's NAICS designation is final unless appealed to SBA's Office of Hearings and Appeals. An appeal must be served and filed within 10 calendar days after the initial solicitation or any amendment affecting the NAICS code or size standard is issued, and the Office of Hearings and Appeals summarily dismisses untimely appeals. Any person adversely affected by the designation may appeal, with an exception for particular sole-source 8(a) contracts. If you think a code is wrong, read the notice the day it posts, because 10 calendar days goes quickly.
How to check your size before you bid
Start with the notice, not your registration. Find the NAICS code and size standard listed on the solicitation, which our line-by-line guide to reading a SAM.gov contract notice shows you how to locate. Next, look that code up in SBA's table or size standards tool to confirm the threshold and whether it is measured in employees or receipts. Then measure your company, together with any affiliates, the way SBA's rules require for that type of standard, as of the day you plan to submit. Finally, confirm that your SAM.gov representations include that code and are current.
To find opportunities in the codes where you are clearly small, browse our set-aside contracts by NAICS sector, such as professional, scientific and technical services (NAICS 54) or administrative, support and waste services (NAICS 56), or filter by program on our set-aside opportunities pages. If you also hold or plan to pursue an SBA certification, our comparison of HUBZone, WOSB, SDVOSB and 8(a) set-asides explains how those programs layer on top of being small, since each one still requires you to meet the size standard for the contract.
Size is the first gate on every set-aside, and it is a gate you can check in an afternoon. Learn the codes you work in, know the standard for each one, watch the code on every notice, and remember that the snapshot is taken on the day you submit your initial offer. Getting that right keeps you from wasting time on bids you cannot win and from winning awards you cannot keep.
The Set-Aside Desk is published by SetAside Signal, an independent publication, not a government agency. This article isn't legal advice; rules change, so confirm details at sba.gov, sam.gov and acquisition.gov. Published Oct 17, 2026.