Estimate your UK Income Tax and National Insurance as a self-employed individual for 2026/27. See where your income goes after expenses, tax and NI.
This calculator estimates your Income Tax and National Insurance as a self-employed individual. It starts with your annual self-employed income, subtracts allowable business expenses to calculate your trading profit, then applies Income Tax and self-employed National Insurance.
Trading profit is your business income (turnover) minus allowable business expenses. It is the figure on which you generally pay Income Tax and Class 4 National Insurance. For example, if your turnover is £50,000 and your expenses are £5,000, your trading profit is £45,000.
Allowable business expenses are costs that are incurred wholly and exclusively for the purposes of your trade. Common examples include office costs, travel, equipment, advertising, and professional fees. This calculator uses a simplified model – always check with HMRC for full guidance.
The amount of tax you pay depends on your trading profit, other income, Personal Allowance, tax bands, and your nation. Self-employed individuals pay Income Tax on their taxable profit and Class 4 National Insurance on profits above the relevant thresholds.
Income Tax is progressive. For 2026/27 in England, Wales and Northern Ireland, the basic rate is 20%, higher rate 40%, and additional rate 45%. Scotland has its own bands. The calculator applies the correct rates based on your selected nation.
Self-employed individuals generally pay Class 4 National Insurance on profits above the Lower Profits Limit and Class 2 National Insurance (a flat rate) if profits exceed the Small Profits Threshold. This calculator uses the applicable rates for the selected tax year.
Illustrative example only: For annual self-employed income of £50,000, allowable expenses of £5,000, and no other income in England for 2026/27:
Self Assessment is the system HMRC uses to collect Income Tax from individuals who are not taxed through PAYE. Self-employed individuals typically need to complete a Self Assessment tax return each year to report their business income, expenses, and tax liability.
Payments on account are advance payments towards your next year's tax bill, based on your previous year's liability. This calculator does not include payments on account in the primary estimate – it shows your estimated annual liability only.
Legitimate ways to reduce your tax bill include claiming all allowable business expenses, making pension contributions, and keeping accurate records. Always consult a qualified tax professional for personalised advice.
It calculates your trading profit by subtracting allowable expenses from your self-employed income, then applies Income Tax and Class 4/Class 2 National Insurance based on the selected tax year and nation.
Yes, self-employed individuals pay Income Tax on their taxable trading profit (after expenses and other deductions).
Yes, self-employed individuals generally pay Class 4 National Insurance on profits and Class 2 National Insurance as a flat rate (subject to current thresholds).
Tax is calculated on your trading profit – your turnover minus allowable business expenses.
Yes, allowable business expenses can be deducted from your turnover to reduce your taxable profit.
Trading profit is your business income after deducting allowable expenses. It is the amount on which you generally pay Income Tax and Class 4 NI.
Yes, the Personal Allowance applies to your total taxable income, including self-employed trading profit.
Scotland has its own Income Tax bands. The calculator applies Scottish rates when Scotland is selected.
Payments on account are advance payments towards your next year's Self Assessment tax bill. This calculator shows your annual liability, not payments on account.
No. This is an independent estimate tool based on published HMRC rates. It is not affiliated with HMRC.