How to read this. Every line shows its working from the 2026/27 sole-trader rules — the personal allowance, the income-tax bands your taxable profit falls into, and the Class 4 NI bands (6% between £12,570 and £50,270, 2% above). Class 2 NI is £0: mandatory Class 2 was abolished on 6 April 2024, so above the Small Profits Threshold you get a qualifying year with nothing to pay.
Scope. This estimates tax on your trading profit alone. Other income, pension contributions, reliefs, and payments on account are handled in the full sole.tax app. It's a calculation tool, not tax advice — your final liability is determined by HMRC.