SIC codes (Standard Industrial Classification codes) describe what a business does. In the UK, every company tells Companies House its nature of business using a five-digit code from the condensed SIC 2007 list, such as 62020 for IT consultancy. In the US, the older SIC system is still published in the OSHA SIC Manual.
Most people meet SIC codes when they set up a limited company and hit the nature of business question. It looks like a formality, and mostly that's true, but picking from the wrong list can get a filing rejected. Here's how the system works on both sides of the Atlantic, as of October 2026.
UK SIC codes and Companies House
Companies House uses a condensed version of the full list of codes published by the Office for National Statistics. GOV.UK describes it as the list for providing Companies House with a description of your company's nature of business. The key rule is simple: only use codes on the condensed list when filing to Companies House, or your filing may be rejected.
Here's the insight people miss. Even a company that does nothing still needs a code. Companies House says a dormant company uses 99999 and a non-trading company uses 74990, so you can't leave the field blank because you haven't started trading.
How the UK list is organised
| Section | Covers | Example code |
|---|---|---|
| A | Agriculture, forestry and fishing | 01110 Growing of cereals |
| F | Construction | 43210 Electrical installation |
| G | Wholesale and retail trade | 47910 Retail sale via mail order houses or via Internet |
| I | Accommodation and food service | 56102 Unlicenced restaurants and cafes |
| J | Information and communication | 62020 Information technology consultancy activities |
| M | Professional, scientific and technical | 70229 Management consultancy activities |
| N | Administrative and support services | 82990 Other business support service activities n.e.c. |
| S | Other service activities | 96020 Hairdressing and other beauty treatment |
The full condensed list runs from Section A to Section U, and n.e.c. means not elsewhere classified, a catch-all inside each group.
Common SIC codes for small businesses
| What you do | Condensed list code and description |
|---|---|
| Software or app development | 62012 Business and domestic software development |
| Freelance IT support | 62090 Other information technology service activities |
| Marketing or advertising agency | 73110 Advertising agencies |
| Design studio | 74100 specialised design activities |
| Bookkeeping | 69202 Bookkeeping activities |
| Accountancy practice | 69201 Accounting and auditing activities |
| Online shop | 47910 Retail sale via mail order houses or via Internet |
| Takeaway or food van | 56103 Take-away food shops and mobile food stands |
| Personal trainer or gym | 93130 Fitness facilities |
| Tutoring or training courses | 85590 Other education n.e.c. |
| Letting your own property | 68209 Other letting and operating of own or leased real estate |
| Dormant company | 99999 Dormant Company |
How to choose the right SIC code, step by step
- Write one sentence on how the business earns most of its income.
- Open the Companies House condensed list and use its search box with a plain word, such as motor, software or cafe.
- Pick the most specific code that matches your main activity, rather than an n.e.c. catch-all, if one fits.
- If you do two distinct things, choose a code for each main activity.
- Check the code appears on the condensed list itself, not only on the longer ONS list.
- Update it the next time you file if the business changes direction.
When your SIC code comes up
You give a SIC code when you register a company, and you confirm or change it when you file your annual confirmation statement. If you're still at the start, my guide on how to register a company in the UK walks through the whole application, and a company that hasn't started trading should read the dormant company guide before choosing 99999.
SIC codes in the US
The US uses a different SIC structure. OSHA publishes the Standard Industrial Classification Manual with a division structure from Division A, Agriculture, Forestry and Fishing, through to Division J, Public Administration, and each division splits into numbered major groups, such as Major Group 01, Agricultural Production Crops, and Major Group 15, Building Construction General Contractors and Operative Builders. OSHA's SIC Search lets you look up a code by keyword. So if a US form, lender or database asks for your SIC code, it's this manual's code it wants, not the UK five-digit one.
| UK SIC (Companies House) | US SIC (OSHA manual) | |
|---|---|---|
| Top level | Sections A to U | Divisions A to J |
| Code format | Five digits, such as 62020 | Numbered major groups, such as 01 or 15, broken down further |
| Where you'll see it | Company registration and Companies House filings | US forms, databases and records that ask for an SIC code |
Why the code matters more than it looks
Your SIC code is public on the company's record, so it's part of how the business presents itself to anyone who looks it up. It's also how official statistics group businesses by activity. That's another reason to pick the most specific accurate code rather than a vague catch-all: it describes what you do in a way strangers can read at a glance.
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My verdict
Don't overthink your SIC code. Choose the most accurate code from the Companies House condensed list for what earns most of your income, add a second only if you run a second distinct activity, and revisit it at your next confirmation statement. The only real mistake is using a code that isn't on the condensed list, because that's what gets filings rejected.
Frequently asked questions
What is a SIC code?
A Standard Industrial Classification code describes a business's main activity. UK companies give Companies House a five-digit code from the condensed SIC 2007 list.
What SIC code should a dormant company use?
Companies House says a dormant company uses 99999 and a non-trading company uses 74990. You still need to provide a code.
Can I use any code from the ONS list?
No. Companies House says to use only codes on its condensed list when filing, or your filing may be rejected.
What SIC code is a consultant?
It depends on the field. IT consultancy is 62020 and general management consultancy is 70229 on the Companies House condensed list.
How many sections are there in the UK SIC list?
The Companies House condensed list runs from Section A, Agriculture, Forestry and Fishing, to Section U, Activities of extraterritorial organisations and bodies.
