NAICS Codes Explained: What Every Small Business Owner Needs to Know

What Is a NAICS Code?

NAICS stands for the North American Industry Classification System. It is a standardized system that classifies every business in the United States, Canada, and Mexico into an industry category using a six-digit code.

Think of it as the government's way of putting every business into a bucket. When a federal agency wants to know how many construction companies exist, or how much revenue the restaurant industry generates, or which businesses qualify for a specific grant program, they use NAICS codes.

Your NAICS code tells the government what your business does. It is one of those behind-the-scenes details that most business owners never think about until they need it, and then it turns out to matter a lot.

Why NAICS Codes Matter for Your Business

Grant Eligibility

Many government grant programs define eligibility by NAICS code. When a federal or state agency creates a grant for "small businesses in the manufacturing sector," they are not using a loose definition. They are looking at specific NAICS codes that fall under manufacturing (codes starting with 31-33). If your business has the wrong code, you might not even show up as eligible, even if your actual work qualifies.

The SBIR and STTR research grant programs, USDA rural business grants, and many state economic development grants all reference NAICS codes in their eligibility requirements. Getting your code right can be the difference between qualifying and being filtered out before anyone reads your application.

SBA Size Standards

The Small Business Administration defines "small business" differently depending on your industry, and they use NAICS codes to make that determination. For some industries, the size standard is based on number of employees. For others, it is based on annual revenue. The thresholds vary significantly from one NAICS code to another.

This matters because SBA size standards determine your eligibility for SBA loan programs, government contracting set-asides, and many other federal programs designed specifically for small businesses. Using the wrong NAICS code could mean you are measured against the wrong size standard.

Government Contracting

If you want to do business with the federal government, your NAICS code is essential. Government contracts are categorized by NAICS code, and small business set-aside contracts specifically use NAICS-based size standards to determine which businesses qualify.

When you register in SAM.gov (the System for Award Management, which is required for federal contracting), you will need to list your NAICS codes. Contracting officers use these codes to find businesses that match the requirements of their solicitations.

Tax and Regulatory Compliance

Some regulatory requirements and tax provisions reference industry classifications. While tax filings typically use the older SIC (Standard Industrial Classification) system, the IRS maps between the two. Your industry classification can affect which regulations apply to your business and how certain tax rules are interpreted.

How to Find Your NAICS Code

Step 1: Go to the Official Source

The Census Bureau maintains the official NAICS code database at census.gov/naics. That is the authoritative source, naics.com is a third-party commercial site with similar lookup tools but is not the federal database. Use the Census Bureau's site for code definitions, the current cross-walks between NAICS revisions, and the official search.

Step 2: Search by What You Do, Not What You Call Yourself

This is important. NAICS codes are based on your primary business activity, not your business name or how you describe yourself. A company called "Smith Digital Solutions" that primarily builds websites would use a code under Web Design Services, not something generic like "technology."

Search for the specific activities your business performs, the things that generate most of your revenue. Try multiple keywords. If you build custom furniture, try "furniture manufacturing," "custom woodworking," and "cabinet making" to see which codes best describe your work.

Step 3: Start Broad, Then Get Specific

NAICS codes are hierarchical. The first two digits represent the broad sector (like 23 for Construction). The third digit narrows it to a subsector. The fourth and fifth digits get more specific. The sixth digit is the most granular level.

Start with the broad sector that fits your business and drill down. The more specific your code, the more accurately it represents what you do.

Step 4: Check What Code You Have Already Used

If you have filed business tax returns, you likely already selected an industry code. Check your previous tax filings to see what you used. If you are registered in SAM.gov, your NAICS codes are listed there. Consistency matters, using different codes in different places can create confusion and complications.

Common NAICS Code Mistakes

Picking the Wrong Code Because It Sounds Right

Business owners often pick a code based on a quick keyword match without reading the full description. Two codes can sound similar but cover very different activities. Always read the detailed description of a code before selecting it.

Using Only One Code When You Need Multiple

If your business performs activities across multiple categories, you can and should list more than one NAICS code. Your primary code should reflect your main revenue-generating activity, but secondary codes capture other significant parts of your business. This is especially important for government contracting, where listing additional codes opens you up to more opportunities.

Never Updating Your Code

Businesses evolve. If your primary activities have shifted significantly since you first selected your NAICS code, it is worth revisiting. The NAICS system itself gets updated every five years by the Census Bureau, and some codes are added, removed, or reclassified during these updates.

Choosing a Code to Game Eligibility

It can be tempting to pick a NAICS code that has a more favorable SBA size standard or opens up more grant opportunities. Do not do this. Your NAICS code should accurately reflect your actual business activities. Misrepresenting your industry classification on government applications can have serious consequences, including disqualification from programs and potential fraud charges.

How NAICS Codes Connect to Grant Discovery

Finding the right NAICS code is not just a one-time administrative task. It is the foundation for discovering government opportunities that match your business. Federal and state grant programs, contracting opportunities, and regulatory requirements are all organized around these codes.

Bizmoon uses your NAICS code as one of the key signals for matching your business to relevant grant opportunities and regulatory changes. When you set up your Bizmoon profile, your NAICS code helps ensure you see the opportunities and compliance updates that actually apply to your industry, not generic results you have to sift through yourself.

Check out our plans to see which level of monitoring fits your business.

Get Your Code Right, Then Put It to Work

Your NAICS code is a small detail that has an outsized impact on your access to government funding and your ability to stay compliant. Take the time to get it right, review it periodically, and make sure it is consistent across your government registrations and filings.

Sign up for Bizmoon to start matching your business to relevant grants, contracts, and regulatory updates based on your industry, location, and business profile.