Free Tax Calculators for the Self-Employed
Estimate your tax savings in seconds
Self-employed people overpay every year — usually by missing deductions or guessing at what they owe. These free calculators estimate your position in seconds, using current HMRC rates, so you know where you stand before you file your Self Assessment.
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Tax Calculators
Self-Employed Tax Calculator
Work out your Income Tax and National Insurance as a sole trader using the 2026/27 rates.
Mileage Allowance Calculator
Work out your HMRC simplified mileage deduction using the 2026–27 rates (55p / 25p per mile).
Home Office Calculator
Work out your HMRC simplified working-from-home flat-rate deduction by the hours you work at home.