NIGP vs NAICS vs UNSPSC Codes: What Contractors Need to Know

A single business can end up juggling three different procurement code systems depending on who it's selling to, and mixing them up is one of the most common sources of confusion for contractors new to government and institutional bidding. Here's what NIGP, NAICS, and UNSPSC each actually classify, who requires them, and how they fit together.

What each code system actually is

NAICS: what industry you're in

The North American Industry Classification System (NAICS) is maintained by the U.S. Census Bureau (jointly with Canada and Mexico) and classifies businesses by industry, not by the specific product or service being purchased. It's the code that determines your SBA size standard and eligibility for small-business certifications like 8(a), HUBZone, and Women-Owned Small Business. NAICS uses a hierarchical 2- to 6-digit code, revised on a five-year cycle.

NIGP: what SLED agencies are buying

The NIGP Code, maintained by NIGP and licensed through Periscope Holdings, is used mainly by US state, local, and education (SLED) agencies to classify the specific commodities and services they procure. Unlike NAICS, it describes the purchase, not your business category, and is available at multiple levels of detail (commonly 3-digit class, 5-digit class-item, and more granular levels beyond that).

UNSPSC: what UN and enterprise buyers are purchasing

The United Nations Standard Products and Services Code (UNSPSC) is a global classification system used on UNGM and by many multinational enterprise procurement systems. It organizes products and services into a four-level hierarchy (segment, family, class, and commodity), coded as an eight-digit number.

Key differences at a glance

Do you need more than one?

Often, yes. A contractor selling professional services to both SLED agencies and UN organizations might reasonably hold a NAICS code for its federal and small-business standing, a NIGP code for the specific state and local agencies it bids with, and a UNSPSC code for its UNGM registration, all describing essentially the same business from three different angles. There's no conflict in holding all three; the mistake is assuming that registering in one system automatically covers you in the others.

How the systems connect

Because SLED and UN buyers use different code systems, NIGP publishes cross-reference tables mapping its codes to NAICS and UNSPSC equivalents. This is what makes it possible to bridge a gap: if an RFP requires a NIGP code you don't hold, but you have a NAICS or UNSPSC code that crosswalks to it, that bridge can sometimes demonstrate relevant coverage. BidBuster uses this same kind of crosswalk logic when matching your Master Profile's registered codes against what an RFP requires, and when identifying potential teaming partners who hold a code you're missing.

Common mistakes

• Assuming one code system covers every buyer. A NAICS registration doesn't automatically satisfy a SLED agency's NIGP requirement or a UN agency's UNSPSC expectation.
• Using an outdated NAICS code after a revision cycle. Codes can be renumbered or split between the five-year NAICS updates. Check your code still matches the current version rather than assuming it's unchanged.
• Registering under codes that are too broad or too narrow. An overly broad code can bury you in irrelevant alerts; an overly narrow one can mean you miss opportunities that use a slightly different but equally applicable code.

Not sure which codes actually apply to your business? Our NIGP, NAICS & UNSPSC code lookup tool searches common NAICS codes directly and points you to the official lookup tools for NIGP and UNSPSC.