How we calculated this
Profit is turnover minus expenses, unless you tick the trading allowance, in which case we deduct £1,000 and ignore expenses. You cannot use both.
Income Tax uses the 2026/27 bands. England, Wales and NI: 20% up to £50,270, 40% to £125,140, 45% above. Scotland uses the six Scottish rates. The personal allowance is £12,570, tapered by £1 for every £2 of income over £100,000.
Class 4 NI is 6% between £12,570 and £50,270, then 2%. We assume this is your only income and you are not claiming Marriage Allowance, pension relief, or student loan deductions.
Sources: Income Tax rates, Scottish Income Tax, self-employed National Insurance.
This is general information, not personal tax advice.