What NAICS code should I use?
Your primary NAICS code should be the code that best describes your primary line of business — usually where you generate the most revenue. You can register multiple NAICS codes on SAM.gov and on state portals to be eligible for bids in all of them. Each NAICS code has its own SBA small-business size standard.
NAICS (North American Industry Classification System) codes are 6-digit codes used by federal and most state agencies to classify businesses and procurement requirements. Each contract opportunity is tagged with one or more NAICS codes; vendors register the NAICS codes that match their business.
Your primary NAICS code should be the one that best describes the work that generates the largest share of your revenue. For example: - A custom software developer: 541511 (Custom Computer Programming Services) - An IT consulting firm: 541512 (Computer Systems Design Services) - A general contractor building commercial buildings: 236220 (Commercial and Institutional Building Construction) - A janitorial firm: 561720 (Janitorial Services) - An engineering services firm: 541330 (Engineering Services)
You can register multiple NAICS codes. SAM.gov, state portals, and most third-party platforms let you select all the codes that apply. Each registered code makes you eligible to receive notifications for and bid on contracts in that NAICS category.
Important: each NAICS code has its own SBA size standard (revenue threshold or employee count). Whether your business qualifies as "small" varies by NAICS — you might be small for 541511 (Custom Programming, $34M revenue limit) but not small for 541512 (IT Services, $34M same), or small for 561720 (Janitorial, $22M) but not small for some construction NAICS that have higher limits.
The SBA Table of Small Business Size Standards is the authoritative reference. Look up each NAICS code your business uses and confirm your small-business status for each.
Tip: when selecting NAICS for a specific bid, use the code the agency listed in the solicitation rather than guessing. Mismatched NAICS can make your bid non-responsive.