A SIC code describes your company's main business activity — here's how to find the right one, and why it matters to keep it accurate.
A Standard Industrial Classification (SIC) code is a 5-digit code used by Companies House, HMRC and the Office for National Statistics to describe your company's economic activity. There are over 600 codes across 21 main industry categories.
You must provide at least one SIC code, and can select up to 4 if your company genuinely carries out several distinct activities. Even a dormant (99999) or non-trading (74990) company must have a code.
How do I find the right code?
- Use the official list of available UK SIC codes on the Companies House website. It has a search box, and only codes from this list can be filed.
- Search by keyword in Inform Direct — the SIC code field works this way both when forming a company and when changing the code for an existing company; start typing a word that describes your business and select from the suggestions.
- Look up similar companies — search the Find and update company information service for businesses offering similar services, to see which code they've used.
There won't always be a code that's an exact match for what your company does — in that case, choose the code(s) that best represent its main activities.
Why getting it right — and keeping it up to date — matters
Under the Economic Crime and Corporate Transparency Act, Companies House now has stronger powers to challenge, reject or remove information on the register that looks incorrect, inconsistent or misleading, and this applies to SIC codes as much as any other filing.
The most common issue Companies House flags is a company still showing a dormant (99999) or non-trading (74990) code after it's started actively trading. If your company's activity has changed since incorporation, update your SIC code rather than leaving the original one in place — a mismatch can also affect how lenders or funders view your company.
How do I update my SIC code?
Change it in Inform Direct, then report it to Companies House via your next confirmation statement — see How Do I Change or Add a SIC Code? for the steps, or Why Might I File a Confirmation Statement Early? if you need to report the change sooner than your normal filing date.
Also known as: SIC code list, SIC code lookup, SIC code search, where to find SIC codes, list of UK SIC codes, which SIC code should I use.
Sources: Companies House blog — Keeping your SIC code accurate (28 May 2026) and Choosing a SIC code for your company.