United Kingdom Self-Employed Tax Calculator 2025/26

Calculate your estimated United Kingdom income tax and National Insurance liability as a self-employed individual or sole trader. Enter your income and allowable expenses to see your 2025/26 tax breakdown based on HMRC Self Assessment rates.

About UK Taxation

Understanding Your Taxes

Income Tax: Charged at 20% (basic rate) on taxable income up to £50,270. Income between £50,270 and £125,140 is taxed at 40% (higher rate), and anything above £125,140 is taxed at 45% (additional rate).
National Insurance Class 4: Self-employed individuals pay 6% on profits between £12,570 and £50,270, and 2% on profits above £50,270.
Personal Allowance: The first £12,570 of income is tax-free. This allowance reduces by £1 for every £2 earned above £100,000.

Tax Reliefs & Allowances

Personal Allowance: £12,570 (2024/25 rate) of tax-free income for all individuals.
Trading Allowance: £1,000 of tax-free trading income for small businesses and side hustles.
Additional reliefs may apply based on your personal circumstances.

This calculator provides estimates based on the 2024/25 tax rates. Tax rules and rates can change annually with government budgets. For professional advice tailored to your specific situation, consult with a qualified tax advisor or accountant.

Worked Example: UK Freelance Web Designer — £45,000 Income

Gross income: £45,000 from freelance web design projects
Allowable expenses: £8,000 (equipment £2,400, software subscriptions £960, home office £312, travel £1,800, professional fees £1,200, phone & broadband £528, training £800)
Taxable profit: £45,000 − £8,000 = £37,000
Personal Allowance: £12,570 tax-free (2024/25)
Income Tax: £37,000 − £12,570 = £24,430 taxable at 20% = £4,886.00
Class 4 National Insurance: 6% on profits between £12,570 and £37,000 = £1,465.80
Total tax liability: £4,886.00 + £1,465.80 = £6,351.80
Take-home pay: £45,000 − £8,000 − £6,351.80 = £30,648.20
Effective tax rate: £6,351.80 ÷ £37,000 = 17.2%
Monthly set-aside: £6,351.80 ÷ 12 = £529.32/month to cover your tax bill

On £45,000 of freelance income with £8,000 in expenses, you would owe approximately £6,352 in Income Tax and Class 4 National Insurance. Setting aside around £529 per month ensures you are prepared for your Self Assessment bill on 31 January. If you miss claiming even £1,000 of those expenses, your tax bill increases by roughly £260 (at the 26% basic combined rate of 20% IT + 6% NIC).