NAICS Codes in Federal Contracting, Explained

NAICS (North American Industry Classification System) codes classify what kind of business an entity is. In federal contracting, the NAICS code assigned to a solicitation does more than describe the work — it sets the size standard that determines which businesses can compete for it as a small business.

How the code is structured

A NAICS code is six digits, and each pair of leading digits narrows the classification. The first two digits are the sector — for example, 33 is Manufacturing. The next two narrow it to a subsector, and the full six digits identify a specific industry — for example, 336411 is Aircraft Manufacturing, under the Manufacturing sector. This site's NAICS 336411 hub page lists every published contractor whose largest classified line of federal contract work falls under that code, alongside the broader Manufacturing sector page one level up.

NAICS code vs. PSC code

Federal contracts carry both a NAICS code and a Product/Service Code (PSC), and they answer different questions. NAICS classifies the contractor's industry — what kind of business it is. PSC classifies what the specific contract action bought — a product, a service, or a type of research and development. The same company can appear under one NAICS code but several different PSC codes across its contracts, because a single industry classification can cover many different specific purchases. A contractor profile on this site lists both, each linked to its own hub page when one exists.

Why the assigned NAICS code determines who can bid as a small business

The Small Business Administration sets a size standard — a revenue cap or an employee-count cap — for every six-digit NAICS code. When an agency solicits a contract under a given NAICS code, only businesses that fall under that code's size standard are eligible to compete for it as a small business, or under one of the set-aside programs that require small-business status. A company can be "small" under one NAICS code — say, a software-services classification with a revenue-based cap — and not small under another, like a manufacturing classification with an employee-count cap, depending on which of its business lines a given solicitation falls under.

Why a contractor's top NAICS code is not always what the company primarily makes or sells

The NAICS code on a contract reflects the classification the awarding agency assigned to that specific solicitation, not necessarily the contractor's own primary business description. A diversified company with contracts across several classifications will show more than one NAICS code on its profile on this site — the "Top NAICS" table lists up to five, ranked by dollar obligations, which is the most reliable way to see where a specific contractor's federal revenue is actually concentrated.

Why the same industry can carry different codes in different years

NAICS is revised on a five-year cycle to keep pace with how the economy actually changes — new industries appear, old ones merge or split. A code valid on a 2021 contract can be retired, renumbered, or redefined by the time a 2026 solicitation is issued, even for what is substantively the same line of work. USAspending.gov and this site record whichever NAICS code was actually assigned to each contract action at the time, so a long-running contractor's "Top NAICS" table reflects the classification in effect when each award was made, not a single code retroactively applied across every year.

NAICS in industry conversation vs. NAICS on a contract

Companies often describe themselves informally by a broader industry category than any single six-digit NAICS code captures — "IT services" or "defense manufacturing," for instance. A federal contract always carries one specific six-digit code, chosen by the awarding contracting officer to match that solicitation's requirement, not a company's own self-description. That is normal and does not mean the code is "wrong" for a diversified business; it means that particular award was classified under whichever code best matched what was actually being purchased.

Where the code list itself comes from

NAICS is maintained by the U.S. Census Bureau and revised every five years; this site uses the current NAICS structure, as published on census.gov/naics. Full sourcing detail, including the exact revision in use, is on the methodology page.

See also: set-aside programs and the sector and industry pages linked from any contractor profile.