Calculate a UK sole trader's income tax plus Class 2 and Class 4 National Insurance on trading profit (2025/26), with net profit and effective rate.
Données vérifiées · July 2026
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A self-employed sole trader pays income tax and National Insurance on trading profit (income minus allowable expenses) via Self Assessment. For 2025/26: income tax at 20/40/45% above the £12,570 personal allowance, Class 4 NIC at 6% between £12,570 and £50,270 then 2% above. Class 2 NIC is no longer compulsory above the Small Profits Threshold.
£45,000 trading profit: £6,486 income tax + £1,946 Class 4 NIC (no Class 2 due) = £8,432, leaving £36,568 net — an 18.7% effective rate.
Enter your trading profit (turnover minus allowable business expenses).
Add any other taxable income so the bands are placed correctly.
Adjust the personal allowance only for edge cases (e.g. blind person's allowance).
Read your income tax, Class 4 NIC and net profit.
Last data update
July 7, 2026
Sources and references
HMRC — Income Tax rates (gov.uk/income-tax-rates); Self-employed National Insurance rates (gov.uk/self-employed-national-insurance-rates), 2025/26.
The data in this calculator is updated regularly to reflect the latest official rates. When in doubt, consult the official sources listed above.
Not if your profits are above the £6,725 Small Profits Threshold — it was abolished for you from April 2024, and the benefit entitlement is credited automatically. Below the threshold you can pay it voluntarily.
This shows the sole-trader tax only. Compare the net figure with the outside-IR35 limited-company take-home to see which is cheaper.