What is a SIC code?
A SIC code is a five-digit number used to classify a company’s business activities. Every SIC code represents a specific type of industry or economic activity, based on the UK Standard Industrial Classification (SIC) system maintained by the Office for National Statistics (ONS).
Companies use SIC codes to tell Companies House what they do. A software development company, a restaurant and an online retailer would each have different SIC codes.
Good to know: A company can have more than one SIC code if it carries out multiple activities. If a company develops software and also provides IT consultancy services, it may use separate SIC codes for each activity. You can register up to four SIC codes for the same business with Companies House.
How do SIC codes work? The system explained
The UK SIC system groups businesses according to the activities they carry out. It starts with broad industry sectors such as construction, retail, or information and communication, before breaking them down into increasingly specific categories.
The resulting categories are compiled into an official SIC code directory maintained by the Office for National Statistics (ONS). When registering a company, businesses choose the code (or codes) from this list that best reflect their main activities.
To give you an idea of how the system works in practice, here are some example categories and SIC codes from the current directory:
Category | SIC Code | Corresponding business activity |
|---|
| | Development of building projects |
Information and communication | | Information technology consulting activities |
| | Driving school activities |
Why do UK businesses need a SIC code?
A SIC code is a legal requirement for most limited companies. SIC codes help Companies House and government bodies maintain accurate records and produce official statistics about different industries and sectors across the UK.
You'll typically need to provide your SIC code when:
Registering a company with Companies House
Filing your annual confirmation statement
Opening a business bank account
Applying for business loans, funding or certain types of insurance
It's important to note that a SIC code doesn't determine what activities your business is allowed to carry out, nor does it affect how much tax you pay.
What types of UK businesses need a SIC code?
Whether or not you need a SIC code depends on your business structure. In general, companies registered with Companies House must provide at least one SIC code to describe their business activities.
The following businesses must have a SIC code:
Note: For a dormant company, use code 99999 – this signals to anyone viewing the public register that the company is dormant and has had no significant accounting transactions. A non-trading company (74990) is typically a newly formed establishment that has not yet commenced any business activities.
The following businesses typically do not need a SIC code:
If your business does require a SIC code, the next step is to find the code that best reflects your main activities.
How to choose the right SIC code for your company
Choosing a SIC code can feel overwhelming at first. There are hundreds of codes to choose from, and your business might not fit neatly into a single category.
However, you don’t need to find a perfect match. The goal is to simply choose the code (or codes) that most accurately represent what your business actually does. The following guide will take you through the process step by step.
1. Identify your main business activity
Start by asking yourself: What does my company primarily do?
Think about the products or services you offer, as well as the activity that generates most of your revenue. For example, if you run an online clothing shop, your main activity is retail. If you build websites for clients, your main activity is likely web development or IT consultancy.
2. Search the official SIC code list
Next, browse the official SIC code list and search for keywords related to your business activities.
Try searching for:
Your main service (e.g. "marketing", "consultancy", "software")
Your products (e.g. "clothing", "furniture", "food")
Your industry (e.g. "construction", "retail", "education")
This should help you narrow down the most relevant options.
3. Choose the closest match
Don't worry if you can't find a code that describes your business perfectly. Many businesses offer a mix of products and services, or operate in niche areas that don't have their own dedicated SIC code.
In these cases, choose the code that most closely reflects your primary activity.
For example, a social media marketing agency might choose a broader advertising or marketing-related SIC code rather than searching for a social media-specific option.
4. Add additional SIC codes if needed
If your company carries out more than one significant activity, you can register multiple SIC codes with Companies House.
For example, a business that operates a café and also provides catering services for events may use separate SIC codes for each activity.
However, avoid selecting codes for activities you don't currently carry out. Your SIC codes should reflect your actual operations, not future plans.
5. Review your SIC codes as your business evolves
Businesses often change over time. You might launch new services, enter new markets, or shift your focus. It's a good idea to review your SIC codes periodically to make sure they still accurately describe your activities.
Pro tip: If you’re struggling to find a match, look at what SIC codes similar businesses in your industry use. You can often find these by searching the Companies House register.
Updating or changing your SIC code
If your company's activities change, you can update your SIC code as part of your annual confirmation statement filing with Companies House.
During the confirmation statement process, you'll be able to review your existing SIC code(s) and make changes if needed. This usually involves searching the SIC code list again, choosing the code (or codes) that best reflect your current activities, and including the updated information in your submission.
Once the confirmation statement has been filed and accepted, Companies House will update your company's public record with the new SIC code(s).
Wrapping up
If you're setting up a limited company, choosing a SIC code is one of the many details you'll need to take care of. Fortunately, it doesn't need to be complicated.
Focus on selecting the code (or codes) that best describe your current business activities, and remember that you can update them later if your company changes direction. Keeping your SIC information accurate will help ensure your Companies House record stays up to date.
Are you ready to officially launch your business? With Tide’s company formation service, you can register your company quickly and easily online. Simply enter your company name and we’ll guide you through the process step by step, including selecting your SIC code(s). You’ll receive your Certificate of Incorporation via email, and you’ll get a free Tide business bank account included in the price.
FAQs
What is a SIC code?
A SIC (Standard Industrial Classification) code is a five-digit number used to classify a company's business activities. Companies use SIC codes to tell Companies House what they do.
How do I find the right SIC code for my business?
Search the official SIC code list and choose the code (or codes) that most closely reflect your company's main business activities. If your business carries out multiple activities, you can register up to four SIC codes with Companies House.
How many SIC codes can a company have?
A company can register up to four SIC codes with Companies House. This can be useful if the business carries out multiple activities.
Can I change my SIC code?
Yes. If your company's activities change, you can update your SIC code as part of your annual confirmation statement filing with Companies House.
What happens if I choose the wrong SIC code?
Choosing the wrong SIC code isn't usually a major issue. If you realise a different code would be a better fit for your business, you can update it through your confirmation statement.
Do sole traders need a SIC code?
No. Sole traders do not usually need a SIC code because they are not registered with Companies House in the same way as limited companies.
