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) at incorporation 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This guide covers what a SIC code is, how to choose one, common codes for UK SMEs, and how to update an out-of-date code.
What a SIC code is
The Standard Industrial Classification system was designed by the Office for National Statistics to categorise economic activity 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). The full five-digit code pinpoints a specific activity (47710 — retail sale of clothing in specialised stores, 62012 — business and domestic software development).
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. 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.
Single-activity businesses pick one code. The other slots are left blank.
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”.
2. Avoid catch-all codes
Two codes you should not pick unless your business genuinely matches:
- 74990 — “Non-trading company”
- 82990 — “Other business support service activities not elsewhere classified”
Both are sometimes used by accountants when the company is dormant or genuinely diversified, but for an active trading business they look vague. Banks, lenders, and procurement systems sometimes flag these as low-quality classifications.
3. Check competitors on the public register
Search for similar businesses on the Companies House register. Look at what SIC codes well-established competitors are using. The codes are often a good guide to what is conventional in your sector.
4. Match to your dominant activity
If you have multiple activities, pick the dominant one as primary and add secondaries. Companies House does not weight the codes you provide — 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
- 62012 — Business and domestic software development
- 62020 — Information technology consultancy activities
- 62090 — Other information technology service activities
- 63110 — Data processing, hosting and related activities
- 73110 — Advertising agencies (including digital agencies)
Retail and e-commerce
- 47910 — Retail sale via mail order houses or via Internet
- 47990 — Other retail sale not in stores, stalls or markets
Hospitality and food
- 56101 — Licensed restaurants
- 56102 — Unlicensed restaurants and cafes
- 55100 — Hotels and similar accommodation
Professional services
- 69201 — Accounting and auditing activities
- 69202 — Bookkeeping activities
- 69109 — Activities of solicitors and other legal advisers
- 70229 — Management consultancy activities
Construction and trades
- 41100 — Development of building projects
- 41201 — Construction of commercial buildings
- 43210 — Electrical installation
- 43220 — Plumbing, heat and air-conditioning installation
Health and care
- 86900 — Other human health activities
- 88100 — Social work activities without accommodation for the elderly and disabled
Creative and media
- 59112 — Video production activities
- 74201 — Portrait photographic activities
- 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 via your next confirmation statement. The procedure:
- Wait for your next confirmation statement — file when the change comes up in the normal filing cycle
- Or file an early confirmation statement — at any time, by filing CS01 immediately. 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.
Why getting it right matters
Three reasons to choose carefully:
Bank account due diligence
Banks run checks against your SIC code as part of know-your-customer processes. A vague or mismatched code can slow account opening or trigger additional verification questions.
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 uses SIC codes for sector-level statistical analysis. 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
- SIC codes are five-digit Standard Industrial Classification codes
- UK companies provide one to four codes from the Companies House condensed list
- Avoid catch-all codes like 74990 and 82990 unless they genuinely fit
- Update via your next confirmation statement (or file an early one)
- The code does not change tax status but is used by banks and ONS
Frequently asked questions
What is a SIC code? A five-digit Standard Industrial Classification code that describes a company’s main business activity. 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. 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 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 genuinely dormant companies. 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/