A SIC code for UK companies is a five digit number that tells Companies House what your business actually does. SIC stands for Standard Industrial Classification, and every limited company registered in the UK must have at least one, chosen from an official list. You pick it when you incorporate, and you can hold up to four codes if your business spans more than one activity.
The short answer to the question everyone asks: choose the code that best describes your main trading activity, using the exact wording from the official 2007 SIC list. It does not affect the tax you pay, it does not lock you into anything, and you can change it later for free. But getting it roughly right matters for credibility, insurance, lending and the occasional bit of official correspondence, so it is worth five minutes of care rather than a random guess.
What a SIC code actually does
SIC codes exist so that government, statisticians and researchers can group businesses by industry. When you file your confirmation statement each year, your SIC code sits on the public register alongside your company name and directors. Anyone searching the Companies House register can see it, including potential customers, suppliers, credit reference agencies and lenders.
Here is what a SIC code does not do, because the myths cause a lot of anxiety:
- It does not set your tax rate or your VAT position. That is a separate matter, and if you are unsure when to register you should read our guide to VAT registration for small businesses.
- It does not restrict what you are legally allowed to do. A UK company can trade in any lawful activity regardless of the code on file.
- It does not need to be perfect. There are only around 730 codes to cover the entire economy, so most businesses settle for the closest reasonable match.
That said, the code is not purely cosmetic. Some banks glance at it when you open an account, some insurers reference it, and lenders and credit agencies use it to benchmark you against your sector. A wildly wrong code (a bakery filed as a management consultancy) can raise eyebrows or trigger extra questions.
Where to find the official SIC code list
There is one authoritative source, and you should use it rather than a third party summary. Companies House publishes the condensed list you must choose from on its own site. You can browse the full Companies House SIC code list and search by keyword. When you incorporate or file a confirmation statement, the online system will only accept a code from this list, so copying a number from an old blog post can fail if that code has been retired.
The codes are grouped into broad sections (agriculture, manufacturing, construction, retail, professional services and so on), then narrowed down to specific five digit entries. The trick is to search for a plain word that describes what you sell, then read the options and pick the most specific match that still fits.
Realistic examples for common small businesses
The easiest way to understand SIC codes is to see what typical UK small businesses use. The table below shows realistic matches. Note that several businesses could reasonably use more than one code, and none of these is the only correct answer.
| Business type | Likely SIC code | Official description |
|---|---|---|
| Freelance web developer | 62012 | Business and domestic software development |
| Independent coffee shop | 56102 | Unlicensed restaurants and cafes |
| Ecommerce clothing store | 47710 / 47910 | Retail sale of clothing / retail via mail order or internet |
| Management consultant | 70229 | Management consultancy activities (other) |
| Plumber or heating engineer | 43220 | Plumbing, heat and air conditioning installation |
| Holiday let owner | 55201 | Holiday centres and villages / self catering accommodation |
| AI services agency | 62090 | Other information technology service activities |
| Bookkeeper or accountant | 69201 | Accounting and auditing activities |
| Marketing agency | 73110 | Advertising agencies |
Two of these deserve a note. If you are running a property let, the classification interacts with tax and licensing rules that go well beyond the code itself, so read our guide on starting a short let business in the UK. And if you are launching in the AI space, the practicalities of pricing and positioning are covered in our piece on starting an AI services business in the UK.
How to choose the right code, step by step
Work through this quick process and you will land on a sensible code in a few minutes:
- Describe your main activity in one plain sentence. Not your aspirations, your actual day to day trade and where most of your revenue comes from.
- Search the official list for the key noun. Type “cafe”, “plumbing”, “consultancy” or “software” into the Companies House search and read the results.
- Pick the most specific match that fits. If you sell only online, a specific retail code beats a generic one. If nothing fits precisely, the “other” codes (often ending in 9) exist for exactly that reason.
- Add secondary codes only if you genuinely have separate activities. A cafe that also does outside catering might add a catering code. Do not pad the list with things you might do one day.
If you truly cannot find anything close, code 82990 (“other business support service activities”) and 96090 (“other personal service activities”) act as catch alls. Use them as a last resort, not a first choice, because a vague code tells credit agencies and customers less about you.
How SIC codes fit into forming a company
You supply your SIC code during incorporation, whether you register directly with Companies House for the £50 online fee or use a formation agent. It is one field among several, so it is easy to rush. It sits alongside the other early admin decisions every founder faces, from opening the right account (see our comparison of the best business bank accounts for UK small businesses) to arranging cover, which we cover in business insurance for UK small businesses.
One more piece of new company admin worth flagging: identity checks are now part of the process. Read our explainer on Companies House identity verification and what directors must do so nothing catches you out at filing time.
How to change your SIC code
Businesses evolve, and your code can follow. You update it through your annual confirmation statement, which you file at Companies House. There is no separate fee for changing the code itself; the confirmation statement carries its own filing fee (£34 online at the time of writing), and you would be filing it anyway at least once a year.
You do not need to wait for the anniversary. You can file a confirmation statement early specifically to update your SIC code if your business has pivoted significantly, for example a printing firm that has become a digital design agency. Keeping the code current is good housekeeping and keeps your public profile accurate for anyone checking you out.
Frequently asked questions
Can I have more than one SIC code?
Yes. A UK company can hold up to four SIC codes. List your main activity first, then add genuine secondary activities. Most small businesses only need one, and there is no benefit in filling all four slots for the sake of it.
Does my SIC code affect the tax I pay?
No. Corporation tax, VAT and PAYE are all handled through HMRC and are entirely separate from the SIC code you file at Companies House. Your code is about industry classification, not taxation.
What happens if I choose the wrong SIC code?
Very little in legal terms, because the code does not restrict your trading. However, a clearly wrong code can look sloppy to lenders and credit agencies and may prompt questions when you apply for finance or insurance. If you spot a mistake, correct it on your next confirmation statement.
Do sole traders need a SIC code?
No. SIC codes apply to registered companies at Companies House. Sole traders who are not incorporated do not file a code, though HMRC will ask you to describe your trade when you register for Self Assessment. If you are weighing up whether to incorporate, our guide to what counts as a small business in the UK is a useful starting point.
Can I use a “dormant” SIC code?
Yes. If your company is not trading, Companies House recognises code 99999 for dormant companies. Switch it to a proper trading code once you start doing business.
What to do next
- Write down your main trading activity in one plain sentence, then search the official Companies House SIC list for the closest match.
- Check your current code on the public register and confirm it still reflects what you actually do today.
- If it is out of date, update it on your next confirmation statement, or file one early if your business has clearly pivoted.
- While you are tidying up your company admin, make sure the rest of your setup is sound, from banking to insurance to identity verification, so your public record is accurate and lender ready.
