What is a SIC code? How to choose and change yours

What is a SIC code?

A SIC code is a five-digit code that describes a company's main economic activity. Companies House asks for it when a company is formed and on each confirmation statement. Every company must give at least one SIC code, and it can give up to four if it carries out a range of different activities.

SIC stands for Standard Industrial Classification. GOV.UK describes the SIC code as the number that identifies what your company does. On the Companies House register, it is shown on the company's overview page under 'Nature of business (SIC)', so anyone who looks the company up can see it.

Companies House says SIC codes also feed into data used by Companies House, HMRC and the Office for National Statistics. Investors and lenders may look at them to understand what a company does.

Source: Keeping your standard industrial classification (SIC) code accurate (Companies House blog)

How to find the right SIC code

Use Companies House's condensed list of SIC codes. It has more than 600 codes, grouped into 21 main industry categories. GOV.UK says to use only codes on the condensed list when filing to Companies House, or your filing may be rejected.

Start with what the company actually does, not what it might do one day. Then narrow down to the most specific code that fits.

1. Write one plain sentence describing what the company does to earn money.
2. Search the condensed list for the key words in that sentence.
3. Pick the most specific code for the main activity. Codes ending 'n.e.c.' (not elsewhere classified) are for activities no other code covers.
4. Add up to three more codes only for other real activities.
5. If you are unsure, look up similar companies on the Companies House register to see how they describe themselves, as Companies House suggests.

Source: Standard industrial classification of economic activities (SIC)

SIC codes for common types of company

These codes come from Companies House's condensed list, checked on 6 October 2026. They are examples, not advice for your company. The right code depends on what your company actually does.

Source: SIC codes condensed list (CSV, Companies House)

What SIC code should a dormant company use?

A dormant company still needs a SIC code. Companies House's condensed list includes 99999 'Dormant Company' and 74990 'Non-trading company', and Companies House says that even a dormant or non-trading company must supply a code. Once the company starts trading, change the code so it shows what the company now does.

Companies House says that using a dormant or non-trading code for an active company is one of the most common discrepancies it sees, and one likely to attract scrutiny under its new powers. If you are not sure whether your company counts as dormant, read what is a dormant company.

Source: Keeping your standard industrial classification (SIC) code accurate (Companies House blog)

How to change your SIC code

You change a SIC code by filing a confirmation statement. The statement has an additional information section where you can update the SIC code, alongside the statement of capital, shareholder information and other details. There is no separate SIC code form.

You do not have to wait for your next statement to be due. Companies House says you can file a confirmation statement early if you need to change the code straight away. Filing early means choosing a new confirmation statement date, so your next confirmation statement deadline moves earlier too.

The Companies House fee is £50 online, paid with the first confirmation statement in each 12-month payment period. If the fee for the current period has already been paid, a second statement to change the SIC code does not carry another fee. Every other part of the confirmation statement still has to be checked, including each director's personal code.

Source: Filing your company's confirmation statement

Why an accurate SIC code matters

Since the Economic Crime and Corporate Transparency Act, Companies House can challenge, reject or remove information on the register that appears incorrect, inconsistent or misleading. Companies House says that if your SIC code does not reflect your company's actual activity, you may face filing rejections or delays while the discrepancy is investigated.

Companies House also says lenders and funding bodies use SIC codes to assess eligibility, and a mismatch can cause delays or complications in an application.

Companies House and the Office for National Statistics are discussing a future SIC framework, but Companies House says none has yet been agreed or put in place. For now, use the current condensed list.

Source: Keeping your standard industrial classification (SIC) code accurate (Companies House blog)

Common SIC code mistakes

Leaving the dormant code 99999 or the non-trading code 74990 in place after the company starts trading.

Not updating the code when the business moves into a new sector or stops an activity.

Using a code from another list, rather than the Companies House condensed list. The filing may be rejected.

Picking a general 'n.e.c.' code when a more specific code fits the activity.

Adding codes for activities the company only plans to start. The code should describe what the company actually does.

Filing a confirmation statement early to change the code and then forgetting that the next deadline has moved earlier.

Change your SIC code with SimpleFilings

SimpleFilings can update your SIC codes through a confirmation statement once you approve it. Our £4.99 service fee is separate from the £50 Companies House fee, which applies only if the current 12-month payment period has not already been paid. The other confirmation statement checks still apply, and every director must already have a personal code. We do not decide your company's activity for you: you tell us what the company does and confirm the code.