Self Assessment Tax Calculator UK — Calculate Tax on Self Employment
Calculate income tax and National Insurance on self employment income. Estimate your self assessment tax bill for freelancers sole traders and contractors.
If you are self-employed a freelancer or have income outside PAYE you need to file a self assessment tax return and pay your own tax. Unlike employees your tax is not automatically deducted so you need to set aside money throughout the year. Self-employed individuals pay income tax on profits plus Class 2 and Class 4 National Insurance contributions. Our calculator estimates your total tax bill including payments on account so you can budget properly and avoid surprises when January 31 arrives.
How much tax do self-employed people pay?
Self-employed individuals pay the same income tax rates as employed people 20% basic 40% higher and 45% additional rate. However you also pay Class 2 NI at £3.45 per week and Class 4 NI at 6% on profits between £12570-£50270 plus 2% above that. On £50000 profit you would pay approximately £7486 income tax plus £2670 Class 4 NI plus £179 Class 2 NI totaling around £10335.
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Self-Assessment Tax Calculator
How Tax Calculation Works
Income tax is calculated on your total taxable income after deducting eligible exemptions and deductions from your gross income. The tax is applied progressively — you pay a lower rate on initial income slabs and higher rates only on income that exceeds each threshold. This means moving into a "higher tax bracket" does not mean your entire income is taxed at the higher rate. Understanding marginal vs effective tax rate is crucial: your marginal rate applies only to the last rupee earned, while your effective rate is the average across all slabs.
Tax-Saving Strategies
Under the old regime, maximize deductions: Section 80C allows up to Rs 1.5 lakh through PPF, ELSS, EPF, and life insurance. Section 80D covers health insurance premiums up to Rs 25,000 (Rs 50,000 for senior citizens). Section 80CCD(1B) offers an additional Rs 50,000 deduction for NPS contributions. Home loan interest up to Rs 2 lakh is deductible under Section 24. Under the new regime, the Rs 75,000 standard deduction and lower slab rates may save you more if your total deductions are below Rs 3.75 lakh. Calculate under both regimes before choosing.
Key Information
| Parameter | Details |
|---|---|
| Income Tax Personal Allowance | £12570 |
| Class 2 NI (Self Employed) | £3.45 per week |
| Class 4 NI Rate | 6% (£12570-£50270) + 2% above |
| Self Assessment Deadline | January 31 (online) |
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Use Calculator NowFrequently Asked Questions
How much tax do self-employed people pay?
Self-employed individuals pay the same income tax rates as employed people 20% basic 40% higher and 45% additional rate. However you also pay Class 2 NI at £3.45 per week and Class 4 NI at 6% on profits between £12570-£50270 plus 2% above that. On £50000 profit you would pay approximately £7486 income tax plus £2670 Class 4 NI plus £179 Class 2 NI totaling around £10335.
What expenses can I deduct as self-employed?
You can deduct legitimate business expenses from your revenue before calculating tax. Common deductions include office rent or the proportion of home used for work utility bills phone and internet costs business travel vehicle mileage at 45p per mile for first 10000 miles professional subscriptions accounting fees and equipment. Keep receipts and records for at least 5 years in case of an HMRC enquiry.
What are payments on account?
Payments on account are advance payments toward your next year tax bill. If your self assessment tax bill exceeds £1000 and less than 80% was collected through PAYE HMRC requires two advance payments each equal to half of the previous year bill. These are due on January 31 and July 31. If your income varies significantly you can apply to reduce payments on account to avoid overpaying.
What are the UK income tax bands for 2025-26?
Personal Allowance: £0-£12,570 (0%). Basic rate: £12,571-£50,270 (20%). Higher rate: £50,271-£125,140 (40%). Additional rate: over £125,140 (45%). The personal allowance reduces by £1 for every £2 earned over £100,000, creating an effective 60% rate between £100,000-£125,140.
What is the £100,000 tax trap?
When your income exceeds £100,000, you lose £1 of personal allowance for every £2 over. This creates a hidden 60% effective tax rate between £100,000-£125,140. Pension contributions are the most effective way to bring your income below this threshold and reclaim the allowance.
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Last updated: March 2026