If you run or are setting up a limited company in the UK, you will come across sic codes almost immediately. They look like small, forgettable numbers on a form, but they follow your company for its entire life on the public register. This guide explains exactly what they are, how to pick the right one, and when to update it, so you can get it right the first time and avoid unnecessary headaches.
Key Takeaways
A SIC code is a five-digit standard industrial classification code used by Companies House to describe a company's main economic activities. Every UK limited company must provide at least one code on its company formation application and then confirm or update its sic code annually on the confirmation statement.
A company can have up to four codes, chosen from the official condensed sic code list maintained by the Office for National Statistics and used by Companies House.
Even dormant and non trading companies must use specific SIC codes (99999 and 74990 respectively) to show their current status on the public register.
SIC codes can be changed easily online if the company's activities change, and accuracy matters because banks, insurers, investors, and B2B marketers all rely on these codes to understand what a business does.
The current UK system, SIC 2007, covers 21 main industry categories and was last updated in 2007. A new revision (SIC 2026) is in development to reflect emerging trends in the UK economy.
What Is a SIC Code? (Clear Definition First)
A SIC code, short for standard industrial classification of economic activities, is a five-digit numerical code used across the UK to classify what a business actually does. Think of it as a universal label that tells Companies House, government bodies, and the wider world the nature of your company's trade.
Each standard industrial classification code corresponds to a specific trade description. For example, 62020 means "Information technology consultancy activities", while 47190 means "Other retail sale in non-specialised stores." The current UK standard is UK SIC 2007, which came into effect for Companies House filings from October 2011 onward. Older four-digit codes from previous versions are no longer accepted for new filings, as the current SIC code format consists of five digits, updated in 2007.
SIC codes form part of the wider industrial classification of economic activities. The UK standard industrial classification system is aligned with international frameworks like the UN's ISIC and the EU's NACE at the four-digit level, with the UK adding a fifth subclass digit for greater precision. This alignment means that uk sic codes can be compared with classification data from other countries, making them useful far beyond British shores.
In simple terms, a standard industrial classification sic code is a shorthand that tells anyone checking the public register exactly what your company does for a living.
What Are SIC Codes Used For?
SIC codes serve multiple purposes across regulatory, statistical, and commercial settings. Here is how different groups use them:
Regulatory and public register use. Companies House requires every company's sic code to appear on the public register. This supports transparency and helps regulatory bodies and government bodies understand the makeup of uk companies across different industries. Public records of company classifications are available to anyone who searches the register, so your SIC code is never truly private.
Statistical and policy use. The Office for National Statistics relies on SIC codes to compile national statistics, publish sector reports, and track how business activities shift across regions and years. Government agencies use SIC codes to monitor industry growth and economic trends. This statistical data feeds directly into policy decisions about the UK economy and helps in the identification of emerging markets and the measurement of economic strength.
Commercial use. Banks use SIC codes to analyze business risk when reviewing loan applications, meaning your code can influence your chances of securing a business loan. Insurance underwriters use SIC codes to price commercial insurance policies based on industry hazards. Investors and credit agencies check them when reviewing a limited company's profile. SIC codes also allow comparison of earnings across industries, helping analysts benchmark performance.
Beyond finance, businesses use SIC codes to identify direct competitors and locate potential partners. B2B marketers use them to target companies operating in specific sectors more accurately than keyword searches alone. SIC codes provide a universal framework for organizing business data, which is why they matter well beyond the Companies House filing itself.
What about getting it wrong? Using the wrong sic code will not usually result in a fine from Companies House, but it can distort how lenders, insurers, and customers perceive your company. It may also affect eligibility for grants, sector-specific reliefs, or partnership approaches. Accuracy matters.
How Do SIC Codes Work in Practice?
Each SIC code is a five-digit number where the first two digits describe a broad industry section and later digits narrow down to the exact economic activity. The SIC classification breaks down broad economic sectors into specific trade activities, allowing fine-grained detail.
For example, the digits "47" indicate retail trade. From there:
47110 is "Retail sale in non-specialised stores with food, beverages or tobacco predominating"
47190 is "Other retail sale in non-specialised stores"
Other concrete examples include 56101 for "Licensed restaurants", 71129 for "Other engineering activities", and 96020 for "Hairdressing and other beauty treatment."
The primary SIC code should always reflect the company's main revenue-generating activity. If a company earns 80% of its income from IT consultancy and 20% from training, the IT consultancy code should come first. Secondary codes capture supplementary but genuine business activities.
SIC codes help classify businesses for statistical analysis, and the UK uses a condensed sic code list for filing purposes. This condensed version is a Companies House-friendly subset of the full ONS classification of economic activities. Only codes on the condensed list are accepted when filing; using a code outside it will lead to rejection.
Across the full system, there are 21 main industry categories labelled A through U. To give you a sense of the breadth, here are selected sections and the types of business they cover:
Section | Description | Example Activities Covered |
|---|---|---|
C | Manufacturing | Electronic components, electrical equipment, heating equipment, motor vehicles, motor vehicle parts, household appliances, video equipment, peripheral equipment, office furniture, musical instruments, prepared meals, concrete products, dairy products, tobacco products, petroleum products (excluding petrochemicals manufacture), and petrochemicals manufacture |
D–E | Utilities | Air conditioning supply section, water supply, waste management |
G | Wholesale & Retail | Retail sale in specialised stores, retail trade generally |
L | Real Estate | Real estate activities, real estate investment |
M | Professional & Scientific | Head offices, services producing activities, consultancy on own account |
N | Administrative & Support | Business support service activities, security service activities |
O | Public Administration | Public administration and defence |
Q | Health | Human health and social work activities |
U | Extraterritorial | Extraterritorial organisations and bodies |
This table is not exhaustive, but it shows how SIC codes span the entire economy, from manufacturing motor vehicles to running a security service.
How Many SIC Codes Can a Company Have?
A UK company must have at least one code recorded at Companies House. Companies can select up to four SIC codes if their business activities span multiple areas.
Most straightforward businesses only need one sic code. A single coffee shop, a one-service IT consultancy, or a standalone hairdresser will find that one code covers everything they do. There is no benefit to adding extra codes just for the sake of it.
Multiple codes become appropriate when a company genuinely operates across distinct lines of business. For example, a limited company that:
Sells products online (47910 - Retail sale via mail order houses or via internet)
Operates a physical retail store (47110 - Retail sale in non-specialised stores)
Manufactures its own branded products (13923 - Manufacture of made-up textile articles)
…would reasonably use three codes. The key rule is that each code should accurately represent a genuine, commercially active part of the business, not aspirational plans or trivial side activities.
Adding unnecessary or vague codes dilutes the meaning of your company's classification and can confuse banks or insurers reviewing your profile.
Choosing the Right SIC Code for Your Company
You must choose the most appropriate sic code for your company directly from the Companies House condensed list during the company formation application. Here is a simple process:
Write down 2–3 keywords that describe your main goods or services (e.g. "plumbing", "software development", "childcare").
Search the condensed list using those keywords to find candidate matches.
Read the code descriptions carefully and shortlist the best fits.
Pick one as your primary code, and add up to three secondary codes if needed.
Double-check that every code you have selected reflects a real, ongoing activity.
Think about your company's main business activity over the next 12 months. If your revenue will come primarily from IT consultancy, that should be your primary code, even if you also do occasional training or product sales on the side.
For ambiguous cases, check how similar established companies are classified on the Companies House register. Search for a competitor or peer by name, look at their "Nature of business" field, and see which code they use. Avoid overly generic "other" codes if a more precise option exists, but if no exact match appears, choose the closest available appropriate sic code that reasonably reflects your main business activities.
Finding Your SIC Code on Companies House
The easiest way to find or confirm a company's sic code is to search for its name or registration number on the Companies House online register and check the "Standard Industrial Classification" field.
New companies will encounter a SIC code selection tool built into online formation platforms. This tool searches the official condensed list in real time as you type keywords. For example:
Typing "plumbing" returns codes related to plumbing, heat, and air conditioning installation
Typing "software development" returns 62012 (Business and domestic software development) and related codes
Typing "childcare" returns codes under education and social work
The condensed list is also available as a downloadable file from GOV.UK, including CSV and PDF formats. The ONS periodically updates this list to reflect new and emerging industries. Bookmark it so you can quickly revisit your choices whenever you prepare a confirmation statement or need to review your code for your company.
Entering Your SIC Code on the Company Formation Application
Since 30 June 2016, SIC codes are mandatory for company registration. All new companies must provide at least one code at the point of incorporation. Companies House requires at least one SIC code for registration, and applications without one will be rejected.
Companies formed before June 30, 2016 did not need SIC codes at incorporation - they were only required later on the annual return. That rule has since changed.
Here is what the process looks like in practice:
Online applications: Most online company formation services provide a search box that pulls directly from the condensed list. Type words that describe your activities, and the tool shows matching codes.
Paper form IN01: If you are using the paper incorporation form, you must enter the SIC code(s) manually. The codes must match the condensed list exactly - wrong number of digits or codes not on the list will cause delays or rejections.
Review before submitting: Common causes of rejection include selecting a code not on the condensed list, entering a four-digit code instead of five, or leaving the field blank entirely.
Companies House requires at least one SIC code for incorporation. Getting this step right saves time and avoids unnecessary back-and-forth.
When Do You Need to Provide or Update a SIC Code?
SIC codes matter at three key points in a company's life:
Initial company formation. The SIC code is first submitted during company registration with Companies House. It appears on the public record as soon as the company is incorporated.
Annual confirmation statement. Each year, the company must file a confirmation statement confirming or updating its SIC code(s). This replaced the old annual return system in 2016. SIC codes must be confirmed annually on the confirmation statement, even if nothing has changed.
When the business model shifts. Directors should update the code if the company's main economic activities change significantly - for example, moving from web design to software publishing, or starting a manufacturing arm alongside a retail operation.
If a change happens mid-year and needs to be reflected urgently (perhaps before approaching a lender or investor), directors can submit a confirmation statement early rather than waiting for the normal filing date.
SIC Codes for Dormant and Non-Trading Companies
Even companies with no current business activity must still have a SIC code recorded at Companies House.
SIC code 99999 is used for a fully dormant company - one that carries out no significant accounting transactions and is not currently trading. A dormant company must use this code rather than leaving the field blank.
SIC code 74990 ("Other professional, scientific and technical activities not elsewhere classified") is used for a non trading company that is not actively trading but may still undertake limited activities, such as paying certain costs or holding assets.
When a company moves from trading to dormant or non trading status (or vice versa), the SIC code should be updated on the next confirmation statement so the public register reflects the correct position. These are temporary classifications. Once the company restarts its main business activities, the dormant or non trading code must be replaced with the appropriate active trade codes.
Do LLPs Need to Provide SIC Codes?
Under current UK rules, limited liability partnerships (LLPs) are not required to provide SIC codes either when they are first registered or on their annual confirmation statements.
This is a clear contrast with limited companies. Every ltd company must always have at least one SIC code on record, whereas LLPs are exempt from this requirement at Companies House.
That said, even though LLPs sit outside the formal SIC code requirement, banks, insurers, and HMRC may still ask about their main business activities for their own classification and risk-assessment purposes. If you are deciding between forming a limited company or an LLP, this is one small administrative difference worth noting.
Changing Your Company’s SIC Code
SIC codes are not fixed for the life of the company. They can be updated whenever business activities change.
The standard way to change a company's sic code is by selecting the new code(s) when filing the next confirmation statement via Companies House WebFiling or an authorised agent's portal. SIC codes can be updated in the next confirmation statement without any special paperwork.
If an urgent change is needed - for instance, to reflect a major pivot before approaching a new lender - directors can file a confirmation statement early so the new SIC code appears on the public register straight away.
When you change the main line of business, re-order your multiple SIC codes so that the new primary activity is listed first.
The process takes minutes online. Identify the change, find the new code(s) on the condensed list, file the updated confirmation statement, and the public record updates accordingly.
Where Did UK SIC Codes Come From?
The standard industrial classification system originated in the United States in 1937 as a way to standardise how economic activities were recorded and measured. The UK adopted its own version in 1948, making uk sic codes one of the longest-running business classification systems in the country.
Since then, the UK system has been revised multiple times to keep pace with changes in the economy: major updates came in 1958, 1968, 1980, 1992, and finally the current SIC 2007 framework. SIC codes were last updated in 2007, and the five-digit SIC 2007 codes became mandatory for new UK companies from October 2011.
UK SIC codes are designed to align with international systems like the UN's ISIC and the EU's NACE, enabling global comparisons of industrial and economic data. The system currently covers 21 main industry categories, 88 divisions, 274 groups, and over 700 individual codes.
Work is already underway by the ONS on a UK SIC 2026 revision, aligned with NACE Rev.2.1 and ISIC Rev.5, which will expand entries and reflect emerging trends in the digital economy, renewable energy, and other evolving sectors.
FAQ: Defining and Using SIC Codes
The following questions cover common practical concerns that are not fully addressed in the main sections above.
Is there a penalty for using the wrong SIC code?
There is no specific Companies House fine solely for choosing an incorrect SIC code. However, directors have a general legal duty to ensure that statutory information is accurate. Consistently using the wrong sic code can create confusion for banks, insurers, and customers, and it may affect how the company's risk is judged or whether it qualifies for certain sector-specific schemes.
Errors should be corrected at the next confirmation statement, or via an early confirmation statement if an urgent fix is needed. Choosing a clearly misleading code on purpose could raise questions if regulators or stakeholders suspect an attempt to misrepresent the business.
Do SIC codes affect my corporation tax with HMRC?
HMRC does not base corporation tax rates directly on SIC codes, but it may use them as part of its risk-profiling and sector analysis. An accurate SIC code helps HMRC understand what the company does, which can be relevant when reviewing claims for reliefs or allowances that apply only to certain industries.
Your company's accounts and tax computations must always reflect its real activities, regardless of which SIC code has been chosen for Companies House. Keep the SIC code aligned with how the business is described in financial statements and tax filings for consistency.
Can I remove all SIC codes from my company?
A UK limited company must always have at least one SIC code recorded at Companies House while it remains on the register. When filing a confirmation statement, directors can change or reduce the number of codes, but they cannot submit without any SIC code at all.
If the company is dormant and has ceased all trading activities, the correct approach is to use the dormant SIC code 99999 rather than leaving the field blank. The only way to stop having a SIC code entirely is to dissolve the company so it is no longer registered.
Do I need a new SIC code if I expand into a new service?
If the new service is small and incidental, the existing primary SIC code may still be appropriate and no change is required. But if the new activity will become a significant part of the company's turnover, directors should add an additional SIC code or update the primary code to reflect the new main activity.
This update is normally made the next time the company files its confirmation statement, unless there is a strong reason to update immediately. Review your codes whenever you make a major strategic shift, such as entering a new market or phasing out an old product line.
Is my SIC code the same as my VAT, PAYE, or business rates category?
A SIC code is entirely separate from VAT registration, PAYE schemes, and local authority business rates categories. Each of these uses its own rules and reference numbers. Although different bodies may ask similar questions about what the company does, they do not all rely directly on SIC codes for their decisions.
Having a consistent description of activities across all registrations - Companies House, HMRC, local council - helps avoid confusion and follow-up queries. Keep internal records of the company's SIC code alongside tax references so directors and advisers can refer to them together when needed.
