Free tools · Self-employed
Self Assessment tax calculator
Estimate the tax bill behind your sole-trade profit for 2025/26 or 2026/27 — income tax plus Class 4 and Class 2 National Insurance, with student loan. England, Wales & NI.
Your income after allowable expenses.
Estimates for England, Wales & Northern Ireland — Scottish income tax bands differ. Figures are a guide only, calculated on an annual basis, and don't cover every personal circumstance (other income, reliefs, pensions, benefits in kind, marriage allowance, etc.). Always confirm your position at gov.uk or with your accountant.
What's in a sole trader's tax bill
Enter your profit — income after allowable expenses, not turnover. Income tax applies above your £12,570 personal allowance at 20%, 40% or 45%. On top, Class 4 National Insurance takes 6% of profit between £12,570 and £50,270 and 2% above. Class 2 is treated as paid once your profit clears the Small Profits Threshold, so most sole traders owe nothing extra for it.
From April 2026, sole traders over the income threshold report to HMRC quarterly under Making Tax Digital. Our guide to estimating your tax bill under MTD explains how to keep money aside through the year so January isn't a shock.