SIC Codes Explained — Find Your Business Code

What Is a SIC Code?

SIC stands for Standard Industrial Classification. It's a 5-digit code that categorises your business activity. The UK uses the SIC 2007 system (based on the EU NACE classification). Every limited company, LLP, and some sole traders need at least one.

You choose your SIC code when incorporating your company and confirm it (or update it) on your annual confirmation statement. You can have up to four SIC codes if your business does multiple things.

Common SIC Codes

How to Choose the Right Code

1. Describe your main business activity in one sentence
2. Search the Companies House SIC code tool
3. If multiple codes apply, choose the one that represents your PRIMARY activity first
4. You can add up to 3 additional codes for secondary activities
5. If nothing fits perfectly, use the nearest "n.e.c." (not elsewhere classified) code in your sector

Why It Matters

• HMRC uses SIC codes to flag businesses for investigation if reported income doesn't match the sector norm
• Some sectors have specific regulatory requirements triggered by SIC code
• Insurance providers use SIC codes to assess risk and set premiums
• Government grants and COVID-era support schemes were allocated by SIC code
• Business directories and credit reference agencies categorise you by SIC code

Changing Your SIC Code

You can update your SIC code on your next confirmation statement (filed annually). There's no separate form — just amend the code when you file. If your business activity has genuinely changed, update it promptly. There's no penalty for changing it, but there could be consequences for having an incorrect one for extended periods.