Choosing the Right NAICS Codes for Federal Contracting

The North American Industry Classification System (NAICS) code is one of the most consequential choices a federal contractor makes during SAM.gov registration. Your primary NAICS code determines your size standard, influences which set-aside opportunities surface in your searches, and shapes how contracting officers categorize your capabilities. Getting it right from the start — and reviewing it regularly — pays dividends in proposal competitiveness.

How NAICS Codes Are Structured

NAICS codes are six-digit hierarchical identifiers. The first two digits identify the broad sector (e.g., 54 = Professional, Scientific, and Technical Services). Each additional digit narrows the category. For example, 541 (Professional and Technical Services) → 5415 (Computer Systems Design) → 54151 (Computer Systems Design Services) → 541512 (Computer Systems Design Services, excluding embedded systems). Federal contracting primarily uses six-digit codes. Browse our NAICS code pages for descriptions and contracting context.

Choosing Your Primary NAICS Code

Your primary NAICS code should reflect your largest or most strategically important line of business. It determines which size standard applies to you in SAM.gov self-certification — a wrong primary code can make you look larger or smaller than you actually are, affecting set-aside eligibility on contracts that use a different NAICS code. Choose the code that best describes what you primarily sell to the government, not just what you primarily do overall.

Adding Secondary NAICS Codes

SAM.gov allows unlimited secondary NAICS codes. Add every code under which you are prepared to bid and perform competitively. Each additional NAICS code expands the set-aside opportunities that match your profile and increases your visibility in agency searches. However, avoid adding codes purely for marketing — contracting officers will probe relevant experience in every code you claim.

Size Standards by NAICS Code

The SBA table of small business size standards assigns a size threshold to each NAICS code. Most services codes use an annual revenue cap (ranging from $8M to $47M); most manufacturing codes use an employee cap (typically 500 or 1,500 employees). Size is measured at the time you submit an offer, using the three-year average annual revenues or the 12-month average employee count, depending on the measure used for your code.

NAICS Code Changes and Recertification

The Census Bureau updates NAICS codes every five years. When NAICS updates occur, some codes are split, merged, or renumbered. If your primary NAICS code is affected, update your SAM.gov registration during your next annual renewal to reflect the new code. Failure to update can result in your CAGE code record referencing an obsolete code, which may confuse automated opportunity matching systems.

Researching Opportunity Density by NAICS Code

Before adding a NAICS code, research how much federal spending flows through that code in your target agencies. Use FedAtlas.com to see award counts and total dollars by NAICS code and agency. Some NAICS codes have enormous federal spending; others are rarely used in government contracting. Use this data to prioritize your capability development and business development investments.