In short: A Standard Industrial Classification (SIC) code is a five-digit code that describes what your company does. You must give at least one, and can give up to four, when you form a company and on each confirmation statement. Choose the code that best matches your main activity, and update it if your business changes.
When you form a UK company, Companies House asks for your "nature of business". You answer with one or more SIC codes. It looks like a small detail, but the right code matters more than many founders think.
What a SIC code is
The UK Standard Industrial Classification is a list of more than 600 five-digit codes grouped into 21 broad sections, such as manufacturing, construction, retail, information and communication, and professional services. Each code describes a type of business activity. For example, there are separate codes for software development, management consultancy and restaurants.
The government uses SIC codes to produce statistics about the economy. Banks, insurers, suppliers and public bodies also look at them to understand what a company does.
How many codes you need
You must give at least one SIC code and can give up to four. Most small companies need only one or two. List the main activity first.
How to choose the right code
- Write one sentence describing what your company will actually do and how it earns money.
- Search the list of SIC codes on GOV.UK using key words from that sentence.
- Pick the most specific code that matches your main activity.
- Add up to three more only if they describe real, significant activities.
Tips:
- Choose the code for what you do, not who your customers are. A bookkeeper for builders is still a bookkeeping business.
- Avoid general "other" codes if a more specific one fits.
- If you sell online, check whether there is a specific retail code, such as retail sale via mail order or internet.
Special codes: dormant and non-trading
Two codes are only for companies that are not trading:
- 99999 for a dormant company;
- 74990 for a non-trading company.
Companies House says active, trading companies should not use these codes. If you start trading, update your code.
Why accuracy matters now
Under the Economic Crime and Corporate Transparency Act 2023, Companies House can query, reject or remove inaccurate information on the register. A SIC code that clearly does not match your business could lead to questions or delays. Banks may also ask about a code that does not match what you tell them, which can slow down opening an account.
How to change your SIC code
You update your SIC code by filing a Confirmation Statement. You do not need to wait for your normal date. You can file one at any time, and you only pay the Companies House fee (£50 online) once in each 12-month period. Update your code if:
- you start trading after being dormant;
- your main activity changes;
- your current code does not describe what you do.
Possible future changes
Companies House and the Office for National Statistics have discussed a future update to the SIC framework. Nothing has been agreed, and any change would need new legislation. For now, use the current list.
Examples
- A web design agency: a code under computer programming or information technology services.
- An online clothing shop: a code for retail sale via mail order houses or via the internet.
- A wood flooring fitter: a code under floor and wall covering.
- A holding company with no trade of its own: a code for activities of holding companies.
These are examples only. Check the full list to find the best match for your company.
How Form My Company can help
We help you choose the right SIC code as part of every formation, starting with our Digital Package at £290. If your activity has changed, we can update it through our Confirmation Statement service for £190, or as part of our Compliance and Due Diligence review. Unsure which code fits? Call our Edinburgh team on 0131 322 1309.
Frequently asked questions
What is a SIC code?
It is a five-digit code from the UK Standard Industrial Classification that describes what a company does.
How many SIC codes can a company have?
At least one and up to four.
How do I change my SIC code?
File a confirmation statement with the new code. You can do this at any time, and you only pay the Companies House fee once in each 12-month period.
Which SIC code should a dormant company use?
Dormant companies can use 99999. Non-trading companies can use 74990. Trading companies should not use either.
Can Companies House reject my SIC code?
Companies House can query, reject or remove information it believes is inaccurate, including a SIC code that does not match the business.