A SIC code is a five-digit Standard Industrial Classification code that describes your company’s main business activity. UK limited companies provide one (up to four) when setting up a limited company and update them via the confirmation statement. Companies House uses a condensed list of codes, separate from the full Office for National Statistics taxonomy. Picking the right code matters for bank due diligence, statistical reporting, and (occasionally) tax classification.
This guide covers what a SIC code is, how to choose one, common codes for UK SMEs, and how to update an out-of-date code.
Quick answers
- What a Standard Industrial Classification (SIC) code is: The UK SIC classification system is used to categorise business activities in the UK for statistical purposes.
- How many SIC codes you can have: Companies House lets you record up to four SIC codes per company, but you must choose at least one code.
- How to update your SIC code: Companies House does not have a standalone form to change SIC codes.
- Key takeaways: SIC codes are five-digit Standard Industrial Classification codes
What a Standard Industrial Classification (SIC) code is
The UK SIC classification system is used to categorise business activities in the UK for statistical purposes. Companies House uses a condensed version of the ONS list, only codes on the Companies House condensed list can be used in Companies House filings.
Each code is five digits. The first two digits identify the broad sector (for example, 47, retail trade, 62, computer programming), and UK classifications include distinct sector codes across areas such as manufacturing and services. The full five-digit code pinpoints a specific activity (47710, retail sale of clothing in specialised stores, 62012, business and domestic software development), helping government bodies compare data across industries and occupations and measure the uk economy. Industrial classification sic codes are used both for compliance filings and for official data collection and statistics. SIC systems differ by country, so a UK code is not always equivalent to a US code.
The SIC code does not change your company’s tax status, share structure, or filing obligations. It is a classification, not a regulatory designation.
How many SIC codes you can have
Companies House lets you record up to four SIC codes per company, but you must choose at least one code. Multi-activity businesses can pick the most accurate combination, for example, a tech business that builds software (62012) and provides consultancy services (62020) can record both, and more than one code is useful where the company’s activities are varied.
Single-activity businesses pick one code based on the main trade the business engages in. The other slots are left blank.
This choice is made during company formation at incorporation, when at least one code must be submitted.
How to choose
The choice process:
1. Search the condensed list by keyword
Use the Companies House condensed SIC code list at resources.companieshouse.gov.uk/sic. Enter keywords that describe your business activity, “consultancy”, “retail”, “construction”, “software development”, “marketing”, to find the appropriate SIC code that best matches your main activity. If nothing exact appears, try alternative keywords or browse manually to find the most appropriate SIC code.
2. Avoid catch-all codes
Two codes you should not pick unless your business genuinely matches:
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74990, “Non-trading company”, which can fit a company that is not actively trading but still has transactions; a dormant company must still provide a SIC code and will typically use 99999 rather than 74990
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82990, “Other business support service activities not elsewhere classified”
Both are sometimes used by accountants when a company is genuinely diversified, but for an active trading business they look vague. A dormant company is treated separately and must still provide a SIC code.
3. Check competitors on the Companies House public register
Search for similar businesses on the Companies House register. Look at what SIC codes well-established competitors are using, as these appear on the public register alongside other company details. The codes are often a good guide to what is conventional in your sector.
4. Match to your dominant activity
If you have multiple business activities, match the dominant one first and then add secondary codes where more than one code is needed. Companies House does not weight the codes you provide, so the aim is to reflect the business accurately when it engages in several activities, it is up to you to decide order if it matters for your records.
For wider context on confirmation-statement filing where SIC codes are updated, see annual return vs confirmation statement.
Common SIC codes for UK SMEs
Examples by sector:
Technology and digital
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62012, Business and domestic software development
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62020, Information technology consultancy activities
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62090, Other information technology service activities
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63110, Data processing, hosting and related activities
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73110, Advertising agencies (including digital agencies)
Retail and e-commerce
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47910, Retail sale via mail order houses or via Internet
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47990, Other retail sale not in stores, stalls or markets
Hospitality and food
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56101, Licensed restaurants
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56102, Unlicensed restaurants and cafes
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55100, Hotels and similar accommodation
Professional services
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69201, Accounting and auditing activities
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69202, Bookkeeping activities
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69109, Activities of solicitors and other legal advisers
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70229, Management consultancy activities
Construction and trades
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41100, Development of building projects
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41201, Construction of commercial buildings
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43210, Electrical installation
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43220, Plumbing, heat and air-conditioning installation
Health and care
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86900, Other human health activities
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88100, Social work activities without accommodation for the elderly and disabled
Creative and media
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59112, Video production activities
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74201, Portrait photographic activities
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18130, Pre-press and pre-media services
This list is illustrative; the full condensed list runs to several hundred codes.
How to update your SIC code
Companies House does not have a standalone form to change SIC codes. You update them through your next confirmation statement when your business activities change. The procedure:
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Wait for your next confirmation statement, file when the change comes up in the normal filing cycle
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Or file a confirmation statement early, at any time, by filing CS01 immediately if you need the new code to appear on the public register before the next filing date. The £50 annual fee covers further confirmation statements within the same payment period at no extra cost.
Update both the primary SIC code and any secondary codes if needed. You can replace, add, or remove codes within the four-slot maximum.
The change takes effect on filing. A wrong SIC code should be corrected promptly rather than left until much later.
Why getting it right matters
Three reasons to choose carefully:
Bank account due diligence
Businesses are often asked for their SIC code when opening a business bank account, as banks run checks against it as part of know-your-customer processes. A vague or mismatched code can slow account opening, as banks may use it to screen higher-risk or restricted sectors, and it can trigger additional verification questions or even a declined application.
Tax classification
In a small number of cases, SIC code can interact with tax treatment, for example, qualifying for certain reliefs requires a specific industry classification. The SIC code itself is not determinative for tax (HMRC looks at actual activity), but it can flag mismatches that draw attention.
Statistical reporting
ONS and other government bodies use SIC codes for sector-level statistical analysis and comparisons. This helps measure the uk economy by industry and publish comparable data across sectors. While this does not affect your business directly, it is the basis for sector data that lenders, investors, and government use to benchmark.
Key takeaways
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SIC codes are five-digit Standard Industrial Classification codes
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UK limited companies provide at least one code and up to four from the Companies House condensed list
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Avoid catch-all codes like 74990 and 82990 unless they genuinely fit
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Update via your next confirmation statement (or file an early one)
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The code does not change tax status but is used by banks for checks and by government bodies / ONS for statistics
Frequently asked questions
What is a SIC code? A five-digit Standard Industrial Classification code that describes a company’s main business activity. UK SIC is the UK system for classifying business activities, and companies choose at least one code when registering. UK companies record one to four codes at Companies House from the condensed SIC list.
How many SIC codes can my company have? Up to four. Most single-activity businesses use one. More than one code is useful if a single description does not fully cover what the company does. Multi-activity businesses can record up to four to capture the full range.
How do I change my SIC code? Through your next confirmation statement. There is no standalone form. If you have a wrong SIC code and need to correct it before the next filing date, you can file an early confirmation statement. If you need to update immediately, you can file an early confirmation statement at any time within the existing payment period.
What’s wrong with using 74990? 74990 is “Non-trading company”, appropriate for a company not currently carrying on business, but that is not the same as a dormant company for accounting purposes. For active trading businesses it looks vague and can flag with banks and lenders. Pick a code that matches your actual activity.
Where do I find the SIC code list? The Companies House condensed list is at resources.companieshouse.gov.uk/sic. Use keyword search to find codes matching your activity.
Useful resources
Companies House, SIC code list https://resources.companieshouse.gov.uk/sic/
GOV.UK, Standard Industrial Classification https://www.gov.uk/government/publications/standard-industrial-classification-of-economic-activities-sic
Companies House blog, Choosing a SIC code https://companieshouse.blog.gov.uk/2021/10/12/choosing-a-standard-industrial-classification-sic-code-for-your-company/