Inputs
Estimate self-employed Income Tax and National Insurance for a sole trader (Class 2 and Class 4). This is an estimate only.
Last updated: 2025-04-06
Profit after allowable business expenses, before tax.
Optional. If you also have employment income, enter it here to allocate Income Tax bands.
Optional. We estimate dividend tax separately and apply your Personal Allowance to non-dividend income first.
Optional. For this estimate, we assume pension contributions reduce annual income used in the calculation.
Results
Enter your profit to see an estimate.
How to use this calculator
Enter your self‑employed profits and any other taxable income. You can optionally include dividends, pension contributions and student loans. Select the appropriate tax year and nation. The calculator shows your estimated Income Tax, Class 2 and Class 4 National Insurance liabilities and student loan repayments per year, month and week.
Toggle voluntary Class 2 contributions to see the difference when profits are below the Small Profits Threshold. Dividends and other income affect your personal allowance and tax bands, so include them for a complete picture.
How it’s calculated
Self‑employment tax is estimated by first calculating your adjusted net income. Personal allowance is applied and tapered above £100,000. Income Tax bands are applied based on your nation and tax year. Class 4 National Insurance is payable on profits above the Lower Profits Limit at the main and additional rates. Class 2 contributions are due at a flat weekly rate when profits exceed the Small Profits Threshold or when you elect to pay voluntarily.
Student loan repayments and dividend tax are optional additions. Student loans are deducted at 9% of income above the relevant threshold; Postgraduate loans at 6%. Dividends are taxed separately after the dividend allowance. Pension contributions reduce adjusted net income for allowance purposes.
Factors that affect your results
- Profits and other income – total taxable income influences your tax band.
- Nation and tax year – rates and thresholds vary across years and between Scotland and the rest of the UK.
- Voluntary Class 2 NI – paying or opting out changes your total liability.
- Dividends and pension contributions – affect personal allowance and tax bands.
- Student loans – repayments depend on your plan and are optional in the calculator.
This simplified calculator does not include all reliefs and deductions available under Self Assessment. For example, capital allowances, business expenses and marriage allowance transfers are excluded. The figures provided are estimates only.
Frequently asked questions
- Does this include VAT?
- No. VAT is not considered in this calculator. If you are VAT registered, taxes on your supplies are handled separately.
- What about expenses?
- Allowable expenses reduce your profits for tax. Enter your profits after deducting allowable business expenses.
- Are payments on account included?
- This calculator estimates the tax and National Insurance due, but payments on account and balancing payments depend on your previous tax bill.
Sources & updates
Figures are based on HMRC rates and thresholds for the 2025/26 tax year. Last updated April 2025. For detailed assumptions see ourMethodology page.
Estimates only – not financial advice. Seek professional guidance for your specific situation.