EIN Comparison
EIN vs NAICS Code: Two Different Business Numbers (2026)
An EIN identifies your specific business to the IRS. A NAICS code classifies your industry. One is a tax ID, the other a category — they are completely unrelated numbers.
Last updated: July 10, 2026
An EIN and a NAICS code are unrelated. An EIN is a nine-digit federal tax ID that identifies your specific business to the IRS. A NAICS code is a six-digit industry classification code that describes what type of business you operate (e.g., 541511 for custom software). One identifies you; the other categorizes your industry. You may need both on government forms, but they serve completely different purposes.
Owners sometimes see both numbers on a government form and assume they are related. They are not. The EIN identifies your business; the NAICS code labels your industry.
This guide separates the tax ID from the industry code, shows where each is used, explains how to find your NAICS code, and puts the two side by side. For the tax ID basics, see what is an EIN.
EIN vs NAICS Code: Identity vs Industry
An EIN is a 9-digit number that identifies one specific business. A NAICS code is a 6-digit number that classifies an entire industry. One is unique to you; the other is shared across your sector.
| Attribute | EIN | NAICS Code |
|---|---|---|
| What it is | Federal tax identification number | Industry classification code |
| Digits | 9 (XX-XXXXXXX) | 6 (e.g., 541511) |
| Assigned by | IRS | Self-selected (US Census system) |
| Purpose | Identifies your business for tax | Categorizes your industry |
| Unique to you? | Yes | No — shared by an industry |
| Where used | Tax filings, banking, hiring | Contracting, SBA size standards, permits |
The EIN answers "which business is this?" The NAICS code answers "what industry is this?" They never substitute for each other.
Where Each Is Used
Where Are the EIN and NAICS Code Actually Used?
The EIN is used for taxes, banking, and hiring. The NAICS code is used for government contracting, SBA size standards, and some permits. Their use cases barely overlap.
- EIN use cases — filing federal taxes, opening a business bank account, running payroll, and applying for business credit. It identifies the filer on every form.
- NAICS use cases — registering for federal contracts in SAM.gov, qualifying under SBA small-business size standards, completing certain licenses and permits, and government economic statistics.
- Where they meet — some government forms ask for both: the EIN to identify the business and the NAICS code to classify its industry. See industries for how EIN requirements vary by sector.
The EIN is required for nearly every formal business. The NAICS code matters mainly when you interact with government contracting or SBA programs.
How Do You Find Your NAICS Code?
Find your NAICS code with the free US Census Bureau NAICS search tool. You select the code yourself based on your primary business activity — no agency assigns it.
Open the Census NAICS search
Go to the NAICS search tool on the US Census Bureau website. It is free and does not require an account.
Search your business activity
Enter a keyword describing what your business does, such as "software," "landscaping," or "restaurant." The tool lists matching 6-digit codes.
Select your primary code
Choose the code that best fits your main activity. A business can list a primary NAICS code and additional secondary codes where forms allow.
You get your EIN from the IRS, and you select your NAICS code yourself. On the SS-4 form, the IRS asks for your principal business activity in words, not a NAICS number — the code comes into play later for contracting and permits.
Frequently Asked Questions
Is my NAICS code my EIN?
No. Your NAICS code is a 6-digit industry classification that describes what type of business you run, like 541511 for custom software. Your EIN is a 9-digit federal tax identification number that identifies your specific business to the IRS. One categorizes your industry; the other identifies your entity. They are unrelated numbers.
Where do I find my NAICS code?
Find your NAICS code using the free NAICS search tool on the US Census Bureau website. Search a keyword for your business activity and the tool returns the matching 6-digit code. You select your own NAICS code; no agency assigns it. You can update it if your primary business activity changes.
Do I need a NAICS code to get an EIN?
Not exactly. The IRS Form SS-4 asks for your principal business activity in plain language, not a NAICS code number. You describe what your business does. A NAICS code becomes relevant later for government contracting, SBA size standards, and some permits and licenses, rather than for the EIN application itself.
What is a NAICS code used for?
A NAICS code classifies your business by industry for government and statistical purposes. It is used in federal contracting, SBA small-business size standards, some business licenses and permits, and economic data collection. It does not identify your specific business or handle taxes — that is the EIN's job. The NAICS code is about your industry category.
Can two businesses have the same NAICS code?
Yes. Many businesses share the same NAICS code because it describes an industry, not a specific company. Every custom software firm can use 541511. By contrast, every business has its own unique EIN. The NAICS code is a shared category; the EIN is a unique identifier for one entity.
Does my NAICS code appear on tax returns?
A business activity code, based on the NAICS system, appears on some business tax returns like Schedule C and Form 1120 to describe your industry. This is separate from the EIN, which identifies the filer. The activity code categorizes what you do; the EIN identifies who is filing. Both can appear on the same return in different fields.
Can I change my NAICS code?
Yes. You can update your NAICS code when your primary business activity changes, since you select it yourself. Update it in the systems where it matters, such as SAM.gov for federal contracting. Your EIN never changes with it — the EIN stays the same for the life of the business regardless of your NAICS classification.
Is a NAICS code required for a small business?
It depends on your activities. A NAICS code is required if you register for federal contracting in SAM.gov, apply for certain SBA programs, or complete permits that ask for it. A small business that only files taxes and operates locally may never formally need one, but it still has an EIN for tax identification.
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