What Is a SIC Code?
Every UK limited company is assigned at least one SIC code — a five-digit number that classifies what your business does. Short for Standard Industrial Classification, a SIC code tells Companies House the main industry your company operates in.
Whether you're incorporating a new company, filing your annual confirmation statement, or opening a business bank account, you'll encounter SIC codes. This guide explains what they are, how to find the right one, and what to do if yours needs updating.
What Does SIC Stand For?
SIC stands for Standard Industrial Classification. In the UK, the codes are maintained by the Office for National Statistics (ONS) and cover every type of business activity — from software development to hairdressing, from property investment to construction.
Companies House uses a condensed version of the ONS SIC list. Each code is exactly five digits long. For example:
- 62012 — Business and domestic software development
- 68209 — Other letting and operating of own or leased real estate
- 56101 — Licensed restaurants
- 86230 — Dental practice activities
Why Do SIC Codes Matter?
SIC codes serve several practical purposes for your company:
1. Companies House public register Your SIC code appears alongside your company name, registered address, and director details on the publicly searchable Companies House register. Anyone looking up your company can see which industry it operates in.
2. Annual confirmation statement Each year, you must confirm your SIC codes are still accurate when you file your confirmation statement. If your business activities have changed, this is when you update them.
3. Credit checks and business banking Many banks request your SIC code when you apply for a business account or credit facility. Having the correct code can prevent unnecessary delays or additional questions during onboarding.
4. Government statistics The ONS uses SIC data to measure economic activity across industries. Your code contributes to national figures on employment, turnover, and sector output.
5. Regulatory context Certain industries operate under specific regulations or licensing requirements. An accurate SIC code helps ensure the correct rules are associated with your company in government records.
How Many SIC Codes Can a Company Have?
A UK limited company can hold up to four SIC codes. Most companies use just one or two — enough to reflect their main activities.
If your business spans several areas (for example, IT consultancy alongside software development, or construction alongside property investment), you can register multiple codes. You don't need to add a code for every minor activity, but any activity that accounts for a meaningful share of your income or turnover is worth including.
How to Find the Right SIC Code
The best starting point is the ONS condensed SIC list, which is the same list Companies House uses. You can download it directly from the GOV.UK website.
When searching for your code, follow these steps:
- Identify your main activity. Think about what your company primarily does — not what it might do in future or what it does occasionally.
- Search for a matching description. Each code comes with example activities. Read these carefully to confirm you've selected the right category.
- Check for exclusions. Some codes list activities that are specifically excluded. For instance, the management consultancy code excludes financial advisory services, which have their own classification.
- Be specific rather than broad. A precise code (like 62012 for business software development) is better than a catch-all code (like 62090 for other IT services), even if both technically apply.
Common SIC Codes by Business Type
| Business type | SIC code |
|---|---|
| Software development | 62012 |
| IT consultancy | 62020 |
| Management consultancy | 70229 |
| Freelance creative / media | 90030 |
| Buy-to-let / property letting | 68209 |
| Photography | 74202 |
| Hairdressing and beauty therapy | 96020 |
| Restaurant or café | 56101 |
| General construction of buildings | 41201 |
| Dental practice | 86230 |
When Do You Need to Provide Your SIC Code?
At company formation
When you register a new company at Companies House, you must include at least one SIC code. Applications submitted without a valid code are rejected. Formation agents and the Companies House online registration service both let you search and select codes during the process.
On your annual confirmation statement
Every year, your confirmation statement includes a review of your SIC codes. You either confirm they're still correct or update them to reflect any change in your business activities. You can file an updated confirmation statement at any time — you don't have to wait for the annual due date.
When applying for banking or credit
Banks typically ask for your SIC code as part of their due diligence when you open a business account. If your code doesn't match your stated business description, expect follow-up questions.
What Happens If My SIC Code Is Wrong?
Having an inaccurate SIC code won't trigger a fine, but it can cause minor practical complications. The most common issue is that your company appears under the wrong industry category on the Companies House register, which may affect how lenders, investors, or potential business partners perceive your company.
Correcting the code is straightforward. You can update your SIC codes at any time by submitting a new confirmation statement through Companies House WebFiling or your filing software. There's no special procedure and no penalty for the correction itself.
SIC Codes and Your Corporation Tax Return
SIC codes don't appear directly on your company tax return — the CT600 form has no field for them, and HMRC doesn't use them to calculate your corporation tax liability.
However, your industry type does influence which parts of the CT600 are most relevant to your situation. Property investment companies, for example, have specific rules for reporting rental income and property losses. Construction companies may need to account for CIS deductions. Understanding your sector helps ensure your return is accurate and complete.
For a full walkthrough of the company tax return process, see our guide to filing your company tax return.
SIC Codes vs Nature of Business
You may have seen forms (including bank applications) that ask for your "nature of business" rather than a SIC code. These mean the same thing in practice. When you register a company, the SIC code you choose is converted into a short plain-English description — this is what appears as the "nature of business" on Companies House records and in correspondence.
If asked for your nature of business and unsure what to write, describing what your company actually does ("software development", "property letting", "management consultancy") is usually sufficient. Your formation agent or filing software will match it to the appropriate SIC code.
Summary
A SIC code is a five-digit number that classifies your company's business activity at Companies House. You need at least one when you incorporate, and you confirm it annually on your confirmation statement. Choosing the most accurate code keeps your public register entry correct and avoids complications with lenders or third parties. If your code is wrong, updating it through a new confirmation statement is quick and penalty-free.