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A NAICS code lookup means finding the North American Industry Classification System code that describes what an organization sells or does. The Census Bureau’s NAICS pages are the official place to search the list, and the code you find then drives other things: which SBA size standard applies, how a federal solicitation is classified, and which industry group an establishment falls in for regulatory purposes. This guide covers how to read a code, where to look it up, and the research-administration situations where a wrong or mismatched code causes trouble. Facts below are as described on the official pages on 2026-10-29.
What NAICS is and who runs it
NAICS is the industry classification used across the United States, Canada and Mexico. The Bureau of Labor Statistics describes it as the product of a collaborative effort between those three countries. The Census Bureau maintains the reference files and the official lookup at census.gov/naics. The BLS Current Employment Statistics program currently uses the 2022 version, NAICS 2022, so make sure any list or spreadsheet you search is the version the receiving agency expects.
How the 2 to 6 digit structure works
Each additional digit narrows the category. BLS lays the hierarchy out in five levels:
| Digits | Level name (BLS) |
|---|---|
| 2 | Sector |
| 3 | Subsector |
| 4 | Industry Group |
| 5 | NAICS Industry |
| 6 | U.S. Industry |
Each level is a subdivision of the one above it, so a four-digit group such as 5417 sits above more specific five- and six-digit codes. BLS also states that the sixth digit of a NAICS classification may be used differently in the U.S., Canada and Mexico. For a cross-border collaboration or subaward, do not assume that a six-digit code means the same thing on both sides of the border.
Where to look up a code
The official Census Bureau NAICS pages
SBA’s contracting guide says: to find your NAICS code, view the NAICS code list at the U.S. Census Bureau. Search by keyword describing your main product or service, then open the candidate code and read its full definition and the activities it includes or excludes before settling on it.
The SBA size standards table and Size Standards Tool
SBA assigns a size standard to each NAICS code. After you have a candidate code, SBA’s table of size standards (and its Size Standards Tool) shows the threshold attached to that code. This is the quickest check on whether the code you picked leads to the size status you expect.
When you need a code: what the official sources say
NAICS codes classify businesses based on the particular product or service they supply. Three situations in research and grants administration show up in the sources:
- Your own business or entity classification. A business will generally have a primary NAICS code, but SBA says it can also have multiple codes if it sells multiple products and services.
- A federal contract you are bidding on. Contracting officers must designate a NAICS code for a contract according to 13 CFR 121.402. Under FAR 19.501(e), solicitations involving set-asides or reserves must specify the NAICS code(s) and corresponding size standard(s). See small business set-asides under FAR 19.5 and the Rule of Two.
- Workplace injury recordkeeping. OSHA’s list of partially exempt industries is organised by NAICS. It includes 5417 (Scientific Research and Development Services), 6113 (Colleges, Universities, and Professional Schools) and 6215 (Medical and Diagnostic Laboratories), and hospitals (622x) are not on it. See OSHA reportable laboratory injuries.
Note that a code you choose for your own registration and the code a contracting officer designates for a contract are different things. The first describes you; the second describes the work being bought.
Steps: find, confirm size standard, apply the code
- Write one plain sentence describing the main product or service the entity supplies for the work in question.
- Search the Census Bureau NAICS pages with the key words from that sentence and shortlist candidate codes.
- Read each candidate’s definition; discard those whose included activities do not match what you actually supply.
- Look the shortlisted codes up in SBA’s size standards table and note the threshold for each.
- If you sell more than one distinct product or service, record more than one code; keep the one that describes the contract or application at hand as the one you enter there.
- For a solicitation, compare your choice with the code the contracting officer designated. Your registration entries are covered in SAM.gov representations and certifications.
Typical timeline phases
- Before a solicitation. Identify your primary code and any additional codes, and check the size standard for each.
- At solicitation publication. Read the NAICS code and size standard the solicitation states. SBA says a NAICS designation can be appealed to its Office of Hearings and Appeals within 10 days of the publication of the solicitation, so this is the narrowest window in the process.
- At offer. Your size is measured against the size standard tied to the designated code, which is why the earlier phases matter.
Common mistakes
- Treating the code as a free choice on a contract. The contracting officer designates it under 13 CFR 121.402; your own preferred code does not replace it.
- Missing the appeal window. SBA gives 10 days from publication of the solicitation for an OHA appeal.
- Looking up the code but not the size standard. The size standard is assigned per code, so two plausible codes can lead to different small-business outcomes.
- Using only one code when the entity does several kinds of work. SBA says multiple codes are allowed.
- Assuming the sixth digit travels. It may be used differently across the U.S., Canada and Mexico (BLS).
- Stopping at a broad group. A four-digit group such as 5417 is a category; the more specific codes beneath it are what describe your actual work.
Related classifications and rules
| Item | How it relates to a NAICS code | Source |
|---|---|---|
| SBA size standards | SBA assigns a size standard to each NAICS code | SBA contracting guide |
| 13 CFR 121.402 | Contracting officers must designate a NAICS code for a contract under it | SBA contracting guide |
| SBA OHA NAICS appeal | Appeal of a designation within 10 days of solicitation publication | SBA contracting guide |
| FAR 19.501(e) | Set-aside and reserve solicitations must specify the NAICS code(s) and size standard(s) (FAR 19.501(e)) | Acquisition.gov |
| OSHA partially exempt industries | List organised by NAICS, including 5417, 6113 and 6215 | 29 CFR 1904, Appendix A to Subpart B |
| BLS Current Employment Statistics | Uses NAICS 2022 | BLS |
For finding who is actually winning federal money, see how to find federal grant awards.
FAQ
What is a NAICS code?
A numeric code, two to six digits, that classifies a business by the particular product or service it supplies. It is used jointly by the United States, Canada and Mexico.
Where do I find my NAICS code?
Use the Census Bureau’s NAICS list, which is where SBA directs businesses to find their code. Then check the code in SBA’s size standards table.
Can an organization have more than one NAICS code?
Yes. SBA says a business will generally have a primary code but can have multiple codes if it sells multiple products and services.
Who chooses the NAICS code for a federal contract?
The contracting officer, under 13 CFR 121.402. You can appeal the designation to SBA’s Office of Hearings and Appeals within 10 days of the solicitation’s publication.
What do the digits mean?
Two digits are the sector, three the subsector, four the industry group, five the NAICS industry and six the U.S. industry. The sixth digit may be used differently in the U.S., Canada and Mexico.
Sources
- U.S. Small Business Administration, Size standards (contracting guide), https://www.sba.gov/federal-contracting/contracting-guide/size-standards, checked 2026-10-29.
- U.S. Bureau of Labor Statistics, NAICS and the CES program, https://www.bls.gov/ces/naics/, checked 2026-10-29.
- U.S. Census Bureau, North American Industry Classification System (the NAICS code list SBA directs businesses to), https://www.census.gov/naics/.
- Acquisition.gov, FAR Subpart 19.5, https://www.acquisition.gov/far/subpart-19.5, checked 2026-10-29.
- 29 CFR Part 1904, Subpart B, Appendix A (partially exempt industries), https://www.law.cornell.edu/cfr/text/29/appendix-A_to_subpart_B_of_part_1904, checked 2026-10-29.
