What Is a NAICS Code? NAICS Structure, Hierarchy & How to Read NAICS Codes
What Is a NAICS Code?
A NAICS code is the standard industry classification used to identify what a specific business location primarily does. In practice, it is the code that best matches the dominant economic activity performed at an establishment, using a hierarchy that narrows from broad sectors to specific 6-digit national industries.
This page explains what a NAICS code means, how the 2-digit to 6-digit structure works, why classification is process-based rather than product-label-based, and how primary activity is determined when a business location performs more than one activity.
Browse the NAICS directory
Search or browse official-style NAICS code pages by hierarchy or activity keyword.
NAICS Code Lookup Directory →See the methodology hub
Use the broader reference center for code boundaries, methodology, and governance guidance.
NAICS Classification Reference Center →Find your code
Use the practical step-by-step page when you need to choose a specific NAICS code.
How Do I Find My NAICS Code? →Public access and services boundary: SICCODE.com maintains free public access to core SIC and NAICS reference materials. Paid services support organizations that require formal verification, documentation, enterprise-scale classification, or application of classification data to internal business records.
In simple terms: a NAICS code is the standard way government and many business data systems label what a business location primarily does.
NAICS code definition: A NAICS code (North American Industry Classification System code) is the official 6-digit industry classification used in the United States, Canada, and Mexico to classify an establishment, meaning a single operating location, by its primary economic activity.
- What it measures: the activity with the largest share of output at that location
- How it groups industries: by similar production processes, not by product names or branding language alone
- Why it matters: it supports standardized reporting, comparison, underwriting, procurement, analytics, and program administration
For legacy context, see What Is a SIC Code?. For direct comparison, see SIC Codes vs. NAICS Codes.
- What a NAICS code is and what it is not
- NAICS structure: 2-digit to 6-digit
- Why the 6th digit matters
- Process-based vs. product-based classification
- How to read a NAICS code
- Primary NAICS code and the establishment rule
- Dominant activity and plurality logic
- Helpful NAICS tools
- Extended 8-digit NAICS codes
- NAICS history and updates
- How NAICS is used
- FAQ
What a NAICS Code Is and What It Is Not
NAICS is a standardized framework used to classify economic activity in a consistent way across North America. It identifies the primary activity of a specific location and places that activity into a hierarchy that becomes more specific as digits are added.
A NAICS code is
- A standardized hierarchical code for industry classification
- Assigned at the establishment level, meaning one operating location
- Designed to group establishments by similar production processes
A NAICS code is not
- A marketing slogan, product tag, or branding label
- A company-wide code that must automatically apply to every location
- A full description of every line of business at a multi-activity site
NAICS Structure: 2-Digit to 6-Digit
NAICS is hierarchical. Each additional digit narrows the meaning, moving from broad sectors to a specific national industry. In many practical workflows, the goal is the most defensible 6-digit NAICS code.
The 6-digit level is commonly the working standard in SBA, banking, insurance, procurement, and classification-sensitive internal systems.
Example drill-down
Sector (2)
11 Agriculture, Forestry, Fishing and Hunting
Subsector (3)
111 Crop Production
Industry Group (4)
1113 Fruit and Tree Nut Farming
Industry (5)
11133 Noncitrus Fruit and Tree Nut Farming
National Industry (6)
111331 Apple Orchards
The same general-to-specific structure applies throughout the NAICS hierarchy.
Why the 6th Digit Matters
National industry refinement: digits 1 through 5 are generally harmonized across the United States, Canada, and Mexico. The 6th digit refines the code at the national-industry level, which is why the most precise official public standard is 6 digits.
When precision matters, validate the 6-digit definition and scope notes on the code detail page.
Process-Based vs. Product-Based Classification
Two businesses can sell the same product but belong to different NAICS industries because their primary process differs. NAICS focuses on whether an establishment primarily produces, resells, distributes, repairs, or provides a service.
Makes bread and sells it
Primary activity is producing the product
Buys bread and resells it
Primary activity is resale rather than production
Same product, different process. Classification follows what the establishment primarily does.
How to Read a NAICS Code
NAICS codes read from left to right, with each level adding specificity. The first digits place the establishment in a broad sector, and the later digits narrow that placement to a specific national industry.
Sector (2)
11 Agriculture, Forestry, Fishing and Hunting
Subsector (3)
111 Crop Production
Industry Group (4)
1113 Fruit and Tree Nut Farming
Industry (5)
11133 Noncitrus Fruit and Tree Nut Farming
National Industry (6)
111331 Apple Orchards
Extended (8)
111331-02 Example of a commercial segmentation layer
The extended example is not part of the official government NAICS structure. It is a vendor segmentation layer used in some commercial datasets.
Primary NAICS Code and the Establishment Rule
Each establishment is assigned one primary NAICS code representing the location’s dominant economic activity. This is an establishment-level rule, not a company-wide branding rule.
Critical rule: a company can have multiple primary NAICS codes across different locations if the dominant activities differ by site.
See: How Many NAICS Codes Can a Company Have? · What Is an Establishment in NAICS? · What Is an Enterprise in NAICS?
Example: one company, different establishment codes
Corporate HQ
551114 Corporate, Subsidiary, and Regional Managing Offices
Manufacturing plant
336111 Automobile Manufacturing
Retail dealership
441110 New Car Dealers
Same company, different locations, different primary activities.
Dominant Activity and Plurality Logic
Clarification: “Primary” does not always mean more than 50 percent. It means the activity with the largest share at the establishment.
In practice, people often talk about a “51 percent rule,” but many establishments are split across several activities. In those cases, the primary NAICS code is still the activity with the largest share, using a consistent measurable proxy such as revenue, value of shipments, payroll, hours, or headcount.
Example A: 51% primary activity, 49% secondary activities.
Example B: primary can still be primary at 40% if the remaining activities are smaller.
Need a defensible selection workflow?
This page defines what a NAICS code is. For step-by-step classification rules, included / excluded boundaries, and methodology, use the NAICS Classification Reference Center.
Helpful NAICS Tools
NAICS lookup and directory
Search by activity keyword or browse the hierarchy, then open the code detail page to validate the definition.
Practical guide: How Do I Find My NAICS Code?
Governance and accuracy references
Use governance references when you need stronger consistency, boundary control, and audit-ready interpretation.
NAICS Classification Reference Center
NAICS Data Governance & Versioning
NAICS Codes for Government Programs & Compliance
Code conversion tools
- NAICS to SIC Cross Reference – find related SIC candidates from a NAICS code
- SIC to NAICS Cross Reference – find related NAICS candidates from a SIC code
Extended 8-Digit NAICS Codes
The official NAICS system ends at 6 digits. Some commercial datasets add a further “extended” layer, often described as 8-digit or marketing-level NAICS, for finer segmentation in list building, market analysis, and internal data operations.
Important: extended codes are not part of the official government NAICS standard. They are commercial segmentation layers built on top of the official 6-digit code.
Explore extended segmentation: Extended NAICS Code Lookup Directory.
NAICS History and Updates
NAICS replaced the older SIC system to modernize industry classification and better align economic activity across North America. It is updated periodically to reflect changes in the economy.
| Year | Milestone | Meaning |
|---|---|---|
| 1997 | NAICS formally adopted | Replaced SIC with a modern process-based North American framework |
| 2002 | NAICS revision | Updated categories to reflect structural economic changes |
| 2007 | NAICS revision | Refined definitions and boundaries |
| 2012 | NAICS revision | Added and updated categories for evolving industries |
| 2017 | NAICS revision | Continued modernization; many systems still reference these codes |
| 2022 | Current published revision | Current public revision in use for many modern workflows |
| 2027 | Next revision cycle | Planned update cycle to reflect continued economic change |
Governance context: NAICS Data Governance & Versioning.
How NAICS Is Used
Programs and reporting
Used in reporting, eligibility checks, and procurement workflows where industry scope needs to be consistent.
Banking and underwriting
Used to group risk, compare peers, and support more consistent interpretation of business activity.
Analytics and benchmarking
Used to compare similar establishments and track industry-specific trends using standardized categories.
FAQ
- Does NAICS end at 6 digits?
Yes. The official government NAICS system ends at 6 digits. Any 7-digit or 8-digit layer is a commercial or internal extension, not part of the official public standard. - Why is the 6th digit called the National Industry level?
Digits 1 through 5 are generally harmonized across the United States, Canada, and Mexico. The 6th digit refines the code at the national-industry level. - Can a company have more than one NAICS code?
Yes. NAICS is assigned at the establishment level, so different locations of the same company can have different primary NAICS codes if their dominant activities differ. - How do I choose the correct NAICS code?
Identify candidate codes, then verify the official definition and scope notes on the code detail page. For a step-by-step process, use How Do I Find My NAICS Code?. - What if an establishment performs multiple activities?
Classify based on the activity with the largest measurable share of output using a consistent proxy such as revenue, value of shipments, payroll, hours, or headcount. - Why does my NAICS code matter for SBA programs?
In many SBA programs, the NAICS code determines which size standard is applied to evaluate small-business eligibility. Accurate classification can affect eligibility and contracting outcomes.
Need help with NAICS classification? Contact Us.