Small Profits Threshold is often confused with the Income Tax allowance. This guide explains what it is, why it matters for Class 2, and how to use the calculator safely.
Because the phrase contains the word “profits”, many users mistakenly treat Small Profits Threshold like an Income Tax allowance. It is not. It is a concept used in Class 2 National Insurance rules for self-employed people.
This calculator uses the selected tax year to decide how to model Class 2 under a simplified approach. That means the same profit can lead to different outcomes across tax years if the official rules changed.
If you are close to the boundary, focus on what you can control: improve your bookkeeping, get your profit estimate more accurate, and verify the official guidance for the correct tax year before filing.
Not tax advice. This page is designed to prevent a common misunderstanding, not to replace official rules.
Last updated: 2026-04-20
No. It is related to Class 2 National Insurance, not Income Tax Personal Allowance.
Tax rules can change by tax year. Always verify the rules for the tax year you are filing.
Use your best profit estimate, then verify your final position using official guidance when you file.
For official rules and definitions, verify with the references below.