Sole trader? Enter your profit and see your income tax, Class 4 National Insurance, payments on account and what you actually keep.
Self Assessment bill = income tax + Class 4 National Insurance on your profit (Class 2 is no longer payable for most).
Income tax works exactly like employment: 0% on the first £12,570 (personal allowance), then 20% to £50,270, 40% to £125,140 and 45% above, with the allowance withdrawn £1 per £2 over £100,000. Scotland has six bands (19%, 20%, 21%, 42%, 45% and 48%), so pick Scotland above. Class 4 NI: 6% of profit between £12,570 and £50,270, then 2% above. Class 2 NI: since April 2024 you don't pay it if your profit is above the Small Profits Threshold, you still build State Pension; below the Small Profits Threshold of £7,105 you can pay £3.65 a week voluntarily.
Payments on account: if your bill tops £1,000, HMRC adds two advance payments toward next year, 50% by 31 January (on top of the bill) and 50% by 31 July.
Sources: gov.uk & HMRC (income tax, Class 4 and Class 2 NI, 2026/27). Illustrative only; assumes a standard tax code, no other income, and no student loan, CGT, dividends or High Income Child Benefit Charge.
Illustrative only, not financial or tax advice. Assumes the standard personal allowance and tax code, self-employment as your only income, and no student loan, dividends, Capital Gains Tax, High Income Child Benefit Charge or trading allowance. Class 2 is shown as nil, which fits most sole traders above the Small Profits Threshold. Always check gov.uk or speak to an accountant.
Compare with employed take-home pay or see the full 2026/27 tax rates.