A SIC code is a five-digit Standard Industrial Classification code that tells Companies House what a company does, for example 62020 for IT consultancy or 68209 for letting property. Every UK company states its business activities when it incorporates, normally as SIC codes, and can list up to four, chosen from the Companies House condensed list based on SIC 2007. Changes are made on the annual confirmation statement, which costs £50 to file online.
What a SIC code is for
The Standard Industrial Classification is the government's scheme for sorting businesses by economic activity. The Office for National Statistics maintains the full classification, and Companies House uses a shorter version: its condensed list has around 730 codes, and Companies House says to "only use SIC codes on the condensed list when filing to Companies House or your filing may be rejected."
The requirement comes from the Companies Act 2006. An application to register a company must include a statement of "its intended principal business activities", and that information "may be given by reference to one or more categories of any prescribed system of classifying business activities". In practice, that system is the SIC list. The code then appears on the public register as the company's "nature of business".
Other people use the code too. Lenders, insurers, suppliers and researchers read it to judge what kind of business you are, and official statistics on the business population are built from it. A code that no longer describes the company can cause questions when you apply for a bank account, finance or insurance.
How the codes are structured
Each code has five digits, and the first two give the broad division. Some examples from the Companies House condensed list:
| Code | Description on the condensed list |
|---|---|
| 62012 | Business and domestic software development |
| 62020 | Information technology consultancy activities |
| 68209 | Other letting and operating of own or leased real estate |
| 69201 | Accounting and auditing activities |
| 70229 | Management consultancy activities other than financial management |
| 47910 | Retail sale via mail order houses or via Internet |
| 64209 | Activities of other holding companies n.e.c. |
| 74990 | Non-trading company |
| 99999 | Dormant Company |
"n.e.c." means "not elsewhere classified". These catch-all codes, such as 82990 (other business support service activities) and 96090 (other service activities), are useful when nothing else fits, but a more specific code is better wherever one exists.
Choosing the right SIC code
- Start with the main activity. List the activity that brings in most of the income first, then add up to three more if the company has other genuine lines of business;
- Search the condensed list. Companies House publishes the list as a CSV file and an online lookup on its SIC guidance page. Search for the words that describe what you do, not your sector name, because many activities sit under unexpected headings;
- Describe what you do, not what you hope to do. A company that will hold property and later develop it is letting property today. You can change the code when the activity changes;
- Use the special codes only when they apply. 99999 is for a dormant company and 74990 for a non-trading company. The rules on what counts as dormant are in our guide to dormant companies.
If you cannot find a code, the paper confirmation statement lets you give "a brief description of the company's business activity" instead, but a code is quicker to process and easier for others to read.
Changing your SIC code
There is no separate form for changing a SIC code. Under section 853C of the Companies Act 2006, where "there has been a change in the company's principal business activities during the confirmation period", the company must notify the registrar "at the same time as it delivers the confirmation statement". Companies House's guidance lists the SIC code first among the changes you can make in the confirmation statement's additional information section.
Online, you update the codes as part of filing the statement. On paper, Part 1 of form CS01 has boxes for new codes and for codes that no longer apply, with space for four of each. The rule also covers a company whose activities changed between applying and incorporating: it must correct the code on its first confirmation statement.
If the activity has changed and you do not want to wait for the anniversary, you can file a confirmation statement early. Companies House says that if you file early, "you will need to choose a new confirmation statement date". The fee is payable once per 12-month payment period, so an early statement can cost another £50 if it falls in a new period. Our guide to filing a confirmation statement explains the process.
Worked example
A company was incorporated in 2023 with code 62020 for IT consultancy. In 2026 it stops consulting and buys two flats to let. On its next confirmation statement it adds 68209 and removes 62020. If the statement is the first one in its 12-month payment period, it pays the £50 annual fee online (£110 on paper), and making the change does not add to that cost.
Is Companies House moving to SIC 2026?
The ONS has published a new classification, UK SIC 2026, which is aligned with the latest EU and UN standards. The ONS describes it as "effective from 14 April 2026" but also says it "is not yet in operational use across ONS (Office for National Statistics) systems" and that "the earliest planned use is in the 2031 Blue Book". It will be introduced in stages, starting with business registers.
For filings, the position has not changed: the paper CS01 still asks for a "SIC code 2007", and Companies House's condensed list is still the 2007-based list. Companies House has not published a date for moving company filings to the new codes, so use the current condensed list for now. The ONS has published correlation tables mapping SIC 2007 to SIC 2026, which show how existing codes will map across.
SIC codes and other company identifiers
A SIC code describes the activity and identifies nothing on its own: thousands of companies share 62020. To identify a particular company, use its company registration number; for tax, HMRC uses the UTR. Getting the SIC code right at incorporation is quick, and keeping it current is part of the confirmation statement routine.
Primary sources: Companies House's SIC guidance and condensed list, confirmation statement guidance, Companies Act 2006 s9 and s853C, and the ONS page on the UK SIC 2026 revision.
If you are forming a company, our company formation team will choose the SIC codes with you, and our company secretarial services keep the codes, confirmation statements and register details up to date each year.