NAICS code
A NAICS code is a six-digit number from the North American Industry Classification System that identifies what economic activity a business is primarily engaged in, not what products it sells. It is maintained jointly by the U.S. Census Bureau, Statistics Canada, and Mexico's INEGI, revised on a five-year cycle, and structured hierarchically from a 2-digit sector down to a 6-digit national industry. Distributors and manufacturers run into it on W-9 forms, vendor registration portals, SBA size-standard determinations for federal contracting, and B2B credit applications — contexts where a buyer is classifying the supplier as a business, not the items in its catalog.
What a NAICS code classifies
NAICS (North American Industry Classification System) sorts business establishments by primary economic activity — what a company mainly does to earn revenue. It is a production-oriented classification: a wholesale distributor of electrical supplies gets a distribution-sector code even though the products it sells (wire, conduit, breakers) would be classified separately if someone were coding the items instead of the business.
The code is hierarchical:
| Digits | Level | Example |
|---|---|---|
| 2 | Sector | 42 — Wholesale Trade |
| 3 | Subsector | 423 — Merchant Wholesalers, Durable Goods |
| 4 | Industry Group | 4236 — Electrical and Electronic Goods Merchant Wholesalers |
| 5 | NAICS Industry | 42361 — Electrical Apparatus and Equipment... Wholesalers |
| 6 | National Industry | 423610 — full detail, U.S.-specific |
The first five digits are shared across the U.S., Canada, and Mexico; the sixth digit is country-specific detail.
NAICS vs. UNSPSC vs. HS code — three different axes
These get confused constantly because they all show up as "codes" on the same procurement forms, but they classify three different things:
| System | Classifies | Typical use |
|---|---|---|
| NAICS | The business (who's selling) | Vendor registration, SBA size standards, tax forms |
| UNSPSC | The product or service being bought (what's being sold) | Spend analysis, procurement catalogs, e-invoicing |
| HS code | The physical good crossing a border | Customs duties, import/export declarations |
A single distributor has one NAICS code (occasionally a couple, if it reports multiple lines of business) but thousands of UNSPSC codes across its catalog, one per product category. Sending a NAICS code where a buyer's system expects a UNSPSC commodity code — or vice versa — is a common cause of rejected vendor records and miscategorized spend.
Where it actually shows up
For most B2B sellers, NAICS surfaces less in the catalog and more in the paperwork around it:
- W-9 and vendor onboarding forms: many buyer AP and procurement systems require a NAICS code to set up a new supplier record
- SBA size standards: federal contracting sets small-business revenue or headcount thresholds per NAICS code, so the code a company self-selects determines which set-asides it can bid on
- Credit and industry benchmarking: lenders and D&B-style credit reports use NAICS to compare a company against industry peers
- Government and enterprise procurement portals: some require a NAICS code alongside, not instead of, product-level classification
Because the code is self-reported and revised only every five years, it drifts: a distributor that has added product lines since its last NAICS selection may be coded under an activity that no longer reflects most of its revenue.
Frequently asked questions
What's the difference between a NAICS code and a UNSPSC code?
NAICS classifies the business — its primary economic activity. UNSPSC classifies the individual products or services being bought and sold. A distributor has one NAICS code for the company but a UNSPSC code for every product category in its catalog. They answer different procurement-form questions and aren't interchangeable.
How often are NAICS codes updated?
NAICS is revised on a five-year cycle by the U.S. Census Bureau in coordination with Canada's and Mexico's statistical agencies, to keep pace with new industries and shifting economic activity. A code assigned several revisions ago can become outdated even if the business itself hasn't changed structurally.
Why does a vendor registration form ask for a NAICS code?
Buyer AP and procurement systems use it to classify suppliers by industry for reporting, spend analysis by supplier category, and — for government and government-adjacent buyers — SBA size-standard and small-business set-aside determinations. It identifies the supplier as a business, separate from whatever product classification (UNSPSC, GPC) applies to individual catalog items.
Can a company have more than one NAICS code?
Yes. A company can list a primary NAICS code plus secondary codes for other significant lines of business, which matters for firms that both manufacture and distribute, or that span more than one federal contracting category. Most vendor forms ask only for the primary code.