SIC codes explained and how to choose and update yours

A SIC code is a five-digit number that tells Companies House what your company does. You choose at least one when you register a company, and you can use up to four to reflect different business activities.

Your codes appear on the public register and help lenders, investors and others understand your business. The aim is straightforward: choose codes that describe what you actually do, and review them as the business changes.

This guide explains how to choose a SIC code, when to update it and how to make the change through a confirmation statement.

What is a SIC code?

SIC stands for Standard Industrial Classification. The system is maintained by the Office for National Statistics, but for company filings you choose from the Companies House condensed list. The FOUNDRS incorporation agent helps you choose the right SIC code using plain English. But there are a few ground rules:

• Every company needs at least one code

• You can have a maximum of four

• Codes are public on the Companies House register

• You can only change them by filing a confirmation statement

Choosing a code is one part of incorporation. Our guide on to how to register a limited company explains the other information you'll need before filing.

How to Register a Limited Company in the UK

How to choose your SIC code

Describe what you actually do, in one sentence

Start with what the business does now, or will do when it begins trading. "We build websites for small businesses" is more useful than "digital transformation solutions". The FOUNDRS incorporation agent helps you do this as part of the formation journey.

Search the condensed list using plain words

Open the condensed list and search for the key noun in your sentence - "software", "consultancy", "letting", "catering". Read the full description of each result rather than stopping at the first close match. The differences can be subtle.

Not sure where to start? Use the free FOUNDRS SIC Code Finder to describe your business in plain English and get suggested codes, or check a code you already have.

Check what similar companies use

Search for two or three competitors or peers on Find and update company information. Companies House itself suggests this as a sense check. It's not proof you've chosen correctly, but if every comparable business uses a different code from you, it's worth asking why.

Cover your main business activities

Choose a code that describes your main activity. If the business has other distinct activities, you can add codes for those too, up to a maximum of four. Focus on what the company actually does rather than things you might try one day.

Avoid the catch-all trap

Some descriptions include "not elsewhere classified". These are valid options when no more specific code fits, but read the alternatives before choosing one. The closest accurate description is more useful than a broad code selected for convenience.

Common founder scenarios

Some situations come up again and again. These are starting points, so always read the full description on the condensed list before you commit.

Your business	Code often used
Buy-to-let property company	68209 - Other letting and operating of own or leased real estate
Buying and selling property	68100 - Buying and selling of own real estate
Holding company owning shares in other companies	64209 - Activities of other holding companies not elsewhere classified
Management or business consultancy	70229 - Management consultancy activities other than financial management
IT contractor or tech consultant	62020 - Information technology consultancy activities
Building software or apps	62012 - Business and domestic software development
Selling products online	47910 - Retail sale via mail order houses or via Internet

If you're setting up a property company to get a mortgage, check the lender's requirements before you choose. Some buy-to-let lenders specify acceptable SIC codes, so it helps to confirm this with your broker or lender early on.

What about dormant and non-trading SIC codes

Two codes need special mention:

99999 - Dormant company

74990 - Non-trading company

These codes describe dormant or non-trading companies; they aren't a substitute for choosing an activity code once your business is trading. Companies House has highlighted dormant or non-trading codes on active companies as a common discrepancy on the register.

If you registered with a dormant code while getting set up, review it when your company starts trading. Don't assume dormancy depends only on whether you've made a sale: other transactions can matter. Companies House and HMRC also have separate dormancy rules. GOV.UK explains the difference.

For the tax side, read our Corporation Tax guide and check the HMRC requirements separately.

Corporation Tax Explained for Limited Companies

How to update your SIC code

You update a SIC code by filing a confirmation statement. You don't have to wait for your annual deadline: you can file early to correct or change your codes. Filing early starts a new review period, so check the date of your next statement afterwards.

Our confirmation statement guide explains the wider checks, deadlines and payment rules involved.

Confirmation Statements Explained: What to File and When

Step by step

1. Check your current codes on Find and update company information and Choose your new codes from the condensed list.

2. If you're filing directly online, get your sign-in details and company authentication code ready, along with any director personal codes required for identity verification.

3. Start a confirmation statement through the Companies House online service.

4. Update the SIC code section. Add new codes and remove any that no longer apply. Think of it as replacing the full list rather than tweaking one entry, so make sure every code you want to keep is there.

5. Check the rest of your company information too. Changes to directors, PSCs or the registered office, for example, need separate filings before you confirm that the records are correct.

6. Submit and pay if a fee is due.

Alternatively you can file your confirmation statement directly through the FOUNDRS dashboard

How much does a confirmation statement cost?

As of October 2026, a confirmation statement costs £50 to file online and £110 on paper. You pay the Companies House fee once in each 12-month payment period. Further statements in that same period don't attract another Companies House fee, although a provider may charge separately. The payment period is separate from the review period and doesn't reset when you file early. Check the latest figures on the Companies House fees page.

Why getting it right matters more now

The Economic Crime and Corporate Transparency Act gave Companies House stronger powers to keep the register accurate. It can now challenge, reject or remove information that looks incorrect, inconsistent or misleading - and that includes SIC codes.

If a code clearly doesn't match your activity, Companies House may query it or delay a filing while it investigates. As a director, you're responsible for keeping the information accurate, even if an accountant or another provider submits it for you.

Keeping your company information organised with FOUNDRS

Review your SIC codes whenever you file your confirmation statement and when your business changes direction. It's a small check that helps keep your public company information accurate.

FOUNDRS guides you through incorporation and lets you file your confirmation statement from your company dashboard, alongside tools for compliance reminders and keeping company documents organised. Already incorporated elsewhere? You can also import your company into FOUNDRS.

For the wider admin checklist, read:

What Happens After You Register a Limited Company?

This guide is for general information only and isn't legal, tax or financial advice. Rules and fees can change, so always check the latest guidance from Companies House and HMRC, or speak to a qualified adviser about your situation.