Features / Self-employed tax calculator
FREE SELF-EMPLOYED TAX CALCULATOR · 2026/27
Get a quick estimate of Income Tax and Class 4 National Insurance from your annual business totals. A useful starting point for deciding what to set aside.
Want a more complete tax estimate? Record all your business income and allowable expenses in TaxSnapper, keep receipts organised and review your estimated tax as you go.
See tax estimates in the app →Download TaxSnapper on iPhone and Android at launch. Estimates depend on the information you record and your circumstances.
Enter totals for the full tax year, or your best full-year forecast. This calculator assumes self-employment is your only income and that you are under State Pension age throughout the tax year.
YOUR SIMPLIFIED ESTIMATE
Enter your annual figures and select “Estimate my tax” to see your breakdown.
Estimated annual tax and Class 4 NI
Annual tax and NI after CIS credit, divided by 12, before payments on account. This is an illustration, not an HMRC instalment schedule or a calculation of what you still need to save.
This is a simplified estimate, not an official HMRC calculation or personalised tax advice. Your final tax bill and payment dates may differ. Only payments on account you enter as already paid towards 2026/27 are credited. Future payments on account for the following tax year are excluded, so your HMRC statement may show a different amount due.
This calculator covers a straightforward sole trader estimate for England, Wales and Northern Ireland, using the 2026/27 rates. It assumes actual allowable expenses rather than the £1,000 trading allowance.
Rates checked against HMRC guidance on 25 October 2026. This calculator is for 2026/27 only.
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Income minus allowable expenses and any eligible mileage gives your business profit. The calculator applies the standard Personal Allowance, reduced above £100,000, then the Income Tax bands. Class 4 NI is calculated separately on profit. Actual CIS deductions and payments on account already paid towards 2026/27 are credited after calculating the annual liability.
No. It estimates the annual liability within the stated assumptions. The remaining balance credits the payments on account you enter for 2026/27. Future payments on account for the following year, other payments and HMRC adjustments can change the amount due on a particular date.
If the CIS deductions and payments on account you enter exceed the estimated tax and NI, the calculator shows a possible overpayment. It is not a guaranteed refund. Your full Self Assessment calculation, other liabilities and HMRC account position determine the outcome.
This page uses a few annual totals for a one-off estimate. TaxSnapper helps you maintain income and expense records, store receipts and review estimates as your records develop. Neither is an official HMRC calculation.
