NIM24153 - Class 4 NICs: Structure: Annual Class 4 NICs maximum from 6 April 2003: Contributors who are self- employed only: Calculation method.

Regulation 100 - Social Security Contributions Regulations 2001 

NIM24152 explains that there is no prescribed annual maximum of Class 2 and 4 NICs Liability for a person who is self-employed only. 

To calculate the amount of Class 2 and 4 NICs payable by someone who has no other employments the following method applies up to 5 April 2024. 

Step 1 

Multiply the amount of profits between the Lower Profits Limit and the Upper Profits Limit by the main Class 4 NICs percentage rate 

Step 2 

Multiply the amount of profits that exceed the Upper Profits Limit by the additional Class 4 NICs percentage rate. 

Step 3 

Multiply the relevant Class 2 NICs rate by the number of weeks of self-employment in the tax year 

Step 4 

Add together the results of steps 1, 2 and 3. 

The result of step 4 is the amount of Class 2 and Class 4 NICs payable by a contributor who is self-employed only. 

Examples of the calculation can be found at NIM24160.

From 6 April 2024

Step 1 

Multiply the amount of profits between the Lower Profits Limit and the Upper Profits Limit by the main Class 4 NICs percentage rate 

Step 2 

Multiply the amount of profits that exceed the Upper Profits Limit by the additional Class 4 NICs percentage rate. 

Step 3

Add together the results of steps 1 and 2. 

The result of step 3 is the amount of Class 4 NICs payable by a contributor who is self-employed only. 

Examples of the calculation can be found at NIM24160.