SIC Codes Explained — What They Are & How to Choose

SIC stands for Standard Industrial Classification. Every UK company must provide at least one SIC code when registering. It is a 5-digit code describing what your business does.

Why They Matter

• HMRC scrutiny — income is benchmarked against your sector. Outliers get flagged.
• Insurance — premiums are assessed by SIC code
• Government grants — allocated by SIC code
• Credit checks — agencies categorise by SIC code
• Statistics — the ONS uses them for economic data

How to Choose

1. Describe your main activity in one sentence
2. Search the Companies House SIC tool
3. Choose the code matching your PRIMARY activity
4. Add up to 3 codes for secondary activities
5. If nothing fits, use the nearest "n.e.c." code

Browse our SIC code directory for the most common codes.

Common SIC Codes

Changing Your Code

Update on your next confirmation statement. No separate form needed. If your activity has changed, update promptly.

Multiple Codes

You can register up to four. The first should be your primary activity (highest revenue). Example: a web agency running courses might use 62012 (software) as primary and 85600 (education) as secondary.