SIC codes (Standard Industrial Classification codes) are five digit numbers that tell Companies House and anyone reading the public register what your company does. You choose your SIC codes yourself when you form a UK limited company, and again each year on your confirmation statement. Nobody assigns them to you, and there is no test that decides whether they are correct, so the responsibility to pick something accurate sits with you.
To choose the right one, describe your main trading activity in plain words, search the official condensed list of codes on gov.uk for the nearest match, and select up to four codes if your business genuinely does more than one thing. If none fit perfectly, pick the closest, and remember you can correct or change it for free later. Getting it roughly right matters because banks, insurers, credit reference agencies and some grant and tender bodies glance at it, though it influences their decisions rather than dictating them.
What a SIC code actually is, and what it is for
The Standard Industrial Classification is a shared coding system used across the UK to group businesses by economic activity. Its main purpose is statistical: it lets government and the Office for National Statistics measure how different sectors are performing without reading every company’s accounts. When you form a company, the code you pick becomes part of that national picture.
For your business, the code has a second life. It appears on the free public record at Companies House alongside your registered office, directors and filing history. Anyone can look it up, including customers, suppliers, lenders and competitors. So while its origins are statistical, in practice it acts as a one line summary of what your company claims to do.
It is worth being clear about what a SIC code is not. It does not register you for VAT, set your tax, grant you any licence, or prove you are qualified to trade. It is a label, not a permission.
Where your SIC code appears and who chooses it
You first choose a code during incorporation, whether you form the company directly through Companies House or through a formation agent or accountant. The online form asks you to enter at least one code and lets you add up to four in total.
After that, your codes are confirmed or updated once a year on the confirmation statement, the annual filing that verifies your company’s core details are still correct. The code shows on the public company profile, so it is visible the moment someone searches your company name or number.
Because you self-select the code, accuracy is on you. There is no Companies House officer checking that a plumber has not accidentally registered as a management consultant. If you are still getting to grips with your filing duties, our guide to Companies House identity verification and what directors must do sets out the wider obligations that now come with running a UK company.
How the five digit code is structured
UK SIC codes follow a hierarchy that narrows from broad to specific. The current version in use is the 2007 condensed list. Reading a code from left to right, the first digits place you in a broad section and division, and the later digits pin down the precise activity.
Take software as an example. Code 62012 covers “business and domestic software development”, while 62020 covers “information technology consultancy activities”. They sit close together but describe different work: one builds software, the other advises on it. That distinction is exactly the kind of detail worth getting right, because the code you pick should match what you actually invoice for.
Searching the official list
The authoritative source is the condensed SIC list published on gov.uk. Companies House also runs a search tool that lets you type a keyword and see matching codes. Use the words a customer would use to describe your service, then check the code definition rather than relying on the label alone.
You can browse the full Standard Industrial Classification of economic activities list on gov.uk, and search codes directly through the Companies House SIC code search. Always confirm a code against these primary sources before filing, because third party lists can be out of date.
Frequently used SIC codes by sector
The table below lists codes that come up often for UK small businesses. Treat it as a starting point, not gospel: always check the exact wording on the official list, because two similar activities can carry different codes.
| Activity | Common code | What it covers | Best for |
|---|---|---|---|
| Management consultancy | 70229 | General management consultancy activities | Advisers, coaches, strategy and operations consultants |
| IT consultancy | 62020 | Information technology consultancy | Tech advisers, implementation and support firms |
| Software development | 62012 | Business and domestic software development | Companies building apps or software products |
| Online retail | 47910 | Retail sale via mail order houses or internet | Ecommerce shops with no physical premises |
| Retail (non-specialised) | 47190 | Other retail sale in non-specialised stores | Shops selling a mixed range of goods |
| General construction | 41201 | Construction of commercial buildings | Builders and main contractors |
| Plumbing and heating | 43220 | Plumbing, heat and air-conditioning installation | Plumbers, heating and gas engineers |
| Electrical installation | 43210 | Electrical installation | Electricians and electrical contractors |
| Cafe or restaurant | 56101 | Licensed restaurants | Restaurants and licensed eateries |
| Takeaway food | 56103 | Take-away food shops and mobile stands | Takeaways and street food vendors |
| Hairdressing and beauty | 96020 | Hairdressing and other beauty treatment | Salons, barbers and beauty therapists |
| Marketing and advertising | 73110 | Advertising agencies | Marketing, advertising and creative agencies |
| Dormant company | 99999 | Dormant company | Companies not trading and holding no significant transactions |
If your work touches several of these, you are allowed to list more than one, up to four codes in total. A firm that both builds software and offers IT consultancy might reasonably carry both 62012 and 62020.
Businesses that span several activities
Plenty of small companies do more than one thing. A design studio might build websites, run marketing campaigns and sell templates online. In that case, list your codes in order of importance, leading with your main revenue source, and add the others up to the limit of four.
Do not stretch to four codes just because you can. A short, honest set of one or two codes reads better to a bank or insurer than four that hint at activities you rarely perform. If your mix of work is complex, the discipline of naming your main activity often clarifies how you should describe the business elsewhere, from your website to your website’s structure and navigation.
Dormant and non-trading companies
If your company is not trading, code 99999 marks it as dormant. This is common for companies formed to protect a name, hold an asset, or sit ready for future use. There is also 74990 for “non-trading company”, used where a business exists but is not actively trading in the usual sense. Choose based on whether the company has any significant accounting transactions: a genuinely dormant company should have none beyond the cost of shares issued at formation.
Who actually looks at your SIC code
In day to day life, most people never check it. But a handful of parties do glance at it, and it can shape how they treat you.
- Banks often review your SIC code when you open a business account, as part of understanding what the business does and its risk profile. A code that clashes with your application can prompt extra questions.
- Insurers may consider your recorded activity when underwriting cover. A code suggesting higher risk work than you actually do could affect quotes.
- Credit reference agencies use sector data in scoring models, so your code can feed into how your business is classified for credit purposes.
- Grant and tender processes sometimes filter or check applicants by sector, and an obviously wrong code can create friction.
Be careful how much weight you give this. In every case the code is an influence, not a hard rule. A bank will look at your actual application and activity, not just a number. The practical takeaway is simply to keep the code accurate so it supports your story rather than contradicting it.
The mistakes people actually make
The most common error is picking a code that sounds right but describes something else. “Management consultancy” (70229) gets chosen by all sorts of businesses that are not consultants, because it feels broad and professional. If you sell products or deliver a trade, that code misrepresents you.
A second mistake is leaving the default or placeholder code from a formation agent unchanged. Some agents pre-fill a generic code to get the incorporation through, expecting you to update it. If you never do, your public record may describe a business you do not run.
A third is using 99999 dormant while actually trading, or forgetting to switch away from dormant once you start trading. If your company is active, a dormant code is inaccurate and can cause confusion with banks and HMRC. A fourth is over-listing: cramming in four codes to look versatile, which dilutes the description and can raise questions rather than answer them.
How to change or correct your SIC code
Changing a SIC code costs nothing. You cannot amend it in isolation with a standalone form; instead you update it on your confirmation statement, which you can file online through Companies House. If you need to correct it before your statement is due, you can file an early confirmation statement to record the change.
Filing a confirmation statement itself carries a modest annual fee (roughly in the low tens of pounds online, and higher on paper, though fees are approximate and subject to change). Updating the SIC code within that statement adds no extra cost. Once filed, the new code appears on the public record.
Because it is free and quick to correct, there is no reason to leave an inaccurate code in place. Review your codes each year when the confirmation statement falls due, and update them if your business has shifted.
SIC codes, tax and your wider filings
Your SIC code does not set your tax. Corporation tax, VAT and PAYE are governed by HMRC based on your actual income, registrations and activity, not by the code on the Companies House register. You can read HMRC’s own guidance on how corporation tax works to see that it makes no reference to your SIC code.
That said, keeping your company’s public details tidy is part of running a compliant business. If you are getting your systems in order, our guide to the SME approach to Making Tax Digital in 2026 and our roundup of the best AI accounting tools for UK small businesses both help you keep filings accurate alongside your Companies House record. If you are close to taking on staff, the complete checklist for hiring your first employee covers the registrations that genuinely do affect your obligations.
Frequently asked questions
Is having the wrong SIC code illegal?
No. There is no penalty for a code that turns out to be a poor match, and Companies House does not prosecute over it. It is still worth correcting, because an inaccurate code can create avoidable friction with banks, insurers and others who read the register. Fix it on your next confirmation statement.
Does my SIC code affect how much tax I pay?
No. Your tax is determined by HMRC based on your actual trading, income and registrations, not by the SIC code held at Companies House. Changing your code will not change your corporation tax, VAT or PAYE position.
Can I have more than one SIC code?
Yes. You can list up to four codes, which suits businesses that genuinely do several things. List the most important activity first, and only add codes for work you actually carry out, rather than everything you might one day do.
What if none of the codes fit my business?
Pick the closest available match. The SIC list is finite and will not describe every niche precisely, so a reasonable approximation is expected and accepted. Many businesses use a broad “other” code within their sector when nothing specific applies, and that is fine.
Do I need to change my code if my business changes direction?
You should, ideally at your next confirmation statement. If a design agency becomes a software company, or a shop moves fully online, updating the code keeps your public record honest and avoids mismatches during bank reviews or credit checks. It costs nothing to change.
What to do next
- Write one plain sentence describing your main trading activity, then a short list of any secondary activities that bring in real revenue.
- Search the official gov.uk SIC list and the Companies House search tool for each activity, and check the full code definition, not just the label.
- Choose one to four codes, leading with your main activity, and enter them at incorporation or update them on your next confirmation statement, which costs nothing extra to amend.
- Diary a yearly review, tied to your confirmation statement, so your code still matches what your business actually does as it grows.
