Tools/SIC to NAICS Converter

    SIC Code to NAICS Converter

    Convert UK SIC 2007 codes to their approximate US NAICS equivalents. Enter a SIC code or search by industry description.

    What Are UK SIC Codes and US NAICS Codes?

    UK SIC codes (Standard Industrial Classification) classify business activities on the Companies House register. Every UK company must report at least one SIC code when registering. The current version is SIC 2007, derived from the EU's NACE Rev. 2 framework.

    US NAICS codes (North American Industry Classification System) serve the same purpose in the United States, Canada, and Mexico. NAICS was developed independently of the European system and uses a different structure, though both cover similar industries.

    Why Convert Between UK SIC and US NAICS?

    • Expanding to the US - UK businesses entering the American market need a NAICS code for federal contracts, state business registrations, and regulatory filings
    • Cross-border market research - comparing UK and US industry data requires matching the classification systems used in each country
    • International due diligence - mapping a UK company's sector to its US equivalent for benchmarking and investment analysis
    • Trade and export compliance - US customs, trade statistics, and government procurement databases use NAICS codes

    How the SIC to NAICS Mapping Works

    Enter a UK SIC code or search by industry description to find the closest US NAICS equivalent. Because SIC 2007 and NAICS were built on different foundations, the mapping is approximate rather than exact. Where a SIC code has multiple possible NAICS matches, the tool returns the closest equivalent - choose the one whose description best fits the specific business activity.

    Limitations of Any SIC to NAICS Conversion

    There is no official crosswalk between UK SIC 2007 and US NAICS. Key differences to be aware of:

    • SIC 2007 is based on the EU NACE Rev. 2 framework; NAICS was developed independently by North American governments
    • Some UK industries have no direct US equivalent and vice versa - particularly in professional services and regulated sectors
    • A single SIC code may correspond to several NAICS codes; a single NAICS code may correspond to several SIC codes
    • Technology and financial services are classified particularly differently across the two systems

    SIC, NAICS, NACE, and ISIC: How the Systems Relate

    UK SIC 2007 was derived from NACE Rev. 2, the EU's classification system, which in turn was derived from ISIC Rev. 4, the United Nations' international standard. NAICS was developed separately by the US, Canada, and Mexico and shares the same high-level industry groupings as ISIC at a broad level, but diverges significantly at the detailed level. Understanding this hierarchy helps when working across multiple international classification systems.

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    Frequently Asked Questions

    What is the difference between UK SIC codes and US NAICS codes?

    UK SIC (Standard Industrial Classification) codes classify business activities in Great Britain and are based on the EU NACE Rev. 2 system. US NAICS (North American Industry Classification System) codes are used in the United States, Canada, and Mexico. Both systems classify industries, but they were developed independently with different structures, groupings, and levels of detail.

    Is there an official SIC to NAICS conversion table?

    No. There is no official crosswalk between UK SIC 2007 and US NAICS because the two systems were built independently and classify activities differently. This tool provides an approximate mapping to the closest NAICS equivalent - useful as a starting point, but the match should always be reviewed against the actual business description.

    Why would I need to convert a UK SIC code to a US NAICS code?

    Common reasons include expanding into the US and needing a NAICS code for federal contracts, tax filings, or business registrations; comparing UK and US market data for industry research; cross-border due diligence where analysts use both code systems; and applying for US grants or regulatory filings that require a NAICS classification.

    Can one UK SIC code map to more than one NAICS code?

    Yes. Because the two systems group industries differently, a single SIC code can correspond to several NAICS codes - and vice versa. Service industries, technology, and professional services in particular are often classified differently across the two systems. Where multiple NAICS codes are possible, choose the one whose description most closely matches the specific activity.

    Can I convert a NAICS code back to a UK SIC code?

    Yes, the mapping works in both directions. Enter a NAICS code or search by US industry description to find the approximate UK SIC equivalent. As with the forward conversion, there may be more than one possible match, and the codes are approximate rather than exact.

    Is this SIC to NAICS converter free?

    Yes. This converter is completely free to use. Enter a SIC code or search by industry description to find the closest NAICS equivalent, with no registration required.

    Who typically uses SIC to NAICS conversions?

    The most common users include UK companies expanding into North America who need a NAICS code for US business registration or contracts; investment analysts comparing UK and US industry data; corporate lawyers and M&A advisers working on cross-border transactions; and compliance teams carrying out international due diligence.

    What is the NACE classification and how does it relate to UK SIC codes?

    NACE (Nomenclature statistique des Activites economiques dans la Communaute Europeenne) is the EU's system for classifying economic activities. UK SIC 2007 was directly derived from NACE Rev. 2, so the two systems are structurally very similar and share the same high-level sections. The main differences are at the most detailed level, where the UK added some country-specific sub-categories.

    Why are SIC codes different in the UK and the USA?

    The US had its own SIC system (US SIC) which was replaced by NAICS in 1997. The UK's SIC 2007 was built on the EU NACE Rev. 2 framework, which developed separately from the North American systems. Because the UK and US systems have different historical origins and update cycles, they classify many industries differently, particularly in services and technology.

    How do I classify a technology or fintech company using NAICS?

    Technology classification in NAICS depends on the primary activity. Software development typically maps to NAICS 541511 (Custom Computer Programming Services) or 541512 (Computer Systems Design Services). Data processing maps to 518210. Financial technology companies may fall under 522390 (Other Activities Related to Credit Intermediation) or 541511 depending on whether their primary activity is financial or technological.

    Are UK SIC codes used outside the UK?

    Other countries use their own national variants of SIC or NACE. Ireland uses NACE Rev. 2 directly, which is closely aligned with UK SIC 2007. Australia, New Zealand, and other Commonwealth countries have their own ANZSIC system. The UK SIC code itself is specific to Companies House registrations in Great Britain.

    What is the ISIC classification and how does it compare?

    ISIC (International Standard Industrial Classification of All Economic Activities) is the UN's international industry classification system. NACE Rev. 2 and UK SIC 2007 are both derived from ISIC Rev. 4, so they share the same high-level structure. NAICS was developed separately and has a different structure at the detailed level. ISIC is primarily used for international statistics rather than national business registration.