SIC to NAICS Crosswalk
Enter a 4-digit SIC code to get the matching NAICS codes, or a 2–6 digit NAICS code for the reverse lookup. Paste several codes separated by commas or new lines. Based on the official U.S. Census concordance.
How it works
The Standard Industrial Classification (SIC) is the 4-digit industry coding system the U.S. used until 1997, when it was replaced by the North American Industry Classification System (NAICS). Countless forms, databases and legacy filings still ask for one or the other, so a reliable SIC to NAICS conversion is a routine need for registrations, insurance applications, government contracting and market research.
This SIC to NAICS crosswalk uses the official concordance published by the U.S. Census Bureau, which matches all 1,004 industries of the 1987 SIC to the corresponding NAICS codes (2,163 mappings in total). Because NAICS regrouped industries by production process rather than by product, many SIC industries were split: one SIC code frequently maps to two or more NAICS codes, and the table shows every candidate so you can pick the one that fits your actual activity.
The reverse direction works too: type a NAICS code (a full 6-digit industry, or just the first 2–6 digits of a sector, subsector or industry group) and the tool lists every SIC code that feeds into it. Everything runs in your browser — no sign-up, and your codes are never sent to a server.
FAQ
Why does one SIC code map to several NAICS codes?
NAICS was built on a different principle than SIC: establishments are grouped by how they produce, not what they sell. When the systems were linked, a single SIC industry was often divided among several NAICS industries. For example, SIC 7372 (Prepackaged Software) split into NAICS 511210 (Software Publishers) and 334611 (Software Reproducing). Choose the NAICS code that describes your establishment's primary activity.
Which NAICS version does this crosswalk use?
The mappings come from the official U.S. Census Bureau concordance between the 1987 SIC and 2002 NAICS. NAICS is revised every five years (2002, 2007, 2012, 2017, 2022), and while most codes are stable, some have since been renumbered or merged — so under the current NAICS 2022 edition a suggested code may differ slightly. Always confirm the final code in the latest NAICS manual.
Where can I find the official SIC to NAICS concordance?
The U.S. Census Bureau publishes the official concordance files (1987 SIC to NAICS and the reverse) on its NAICS concordances page at census.gov/naics. As U.S. government works they are in the public domain, and this tool's dataset is built directly from them.
Need to convert SIC codes in bulk?
Our JSON API converts entire lists of SIC or NAICS codes in one call — ideal for CRM enrichment, compliance screening and data pipelines. 25 free calls per month, no credit card required. See the API.
Results are suggested classifications, not official determinations or legal advice. Data source: U.S. Census Bureau, official 1987 SIC to 2002 NAICS concordance (public domain).