How it works
Estimated bill = Income Tax on profit + Class 4 National Insurance at 6% from £12,570 to £50,270 and 2% above.
A worked example
On £50,000 profit in England, Wales or Northern Ireland, the estimate is £7,486 Income Tax plus £2,245.80 Class 4 NI.
What to keep in mind
2026/27 estimate for a sole trader with no other income. Profit means income after allowable business expenses. Excludes student loans, pension relief, payments on account, Capital Gains Tax, VAT and voluntary Class 2 contributions.
A common question
Do I still pay compulsory Class 2 National Insurance?
For 2026/27, Class 2 is treated as paid when profits reach the Small Profits Threshold. This estimate therefore includes Class 4 contributions, not a compulsory Class 2 charge.
Sources & rates
Rates checked on 24 September 2026.
For general information and planning, not personalised financial or tax advice. Verify important decisions with a qualified adviser.