Class 4 National Insurance is one of the two types of National Insurance (NI) that you pay if you’re self-employed.

The other type is Class 2.

You start paying Class 4 NI once you earn over £9,501 a year (from all your combined income sources).

Class 4 NI is 9% for self-employment profits between £9,501 and £50,000, and 2% on anything above £50,000.

What to remember about Class 4 National Insurance:

• You pay it yourself through a Self Assessment tax return – as with Income Tax on your self-employment earnings
• It is in addition to Class 2 National Insurance
• You must pay Class 4 NI even if you earn less than the Personal Allowance
• If you’re also working as an employee and your total earnings are over £9,501 (e.g. you work in sales during the day and freelance as a tutor in the evenings), you’ll pay both Class 1, Class 2, and Class 4 NI. 

For more information, you can use this employed and self-employed calculator to see how much NI you should pay.