Self-Employed Tax Calculator UK — Calculate Your Tax Bill
Calculate income tax and National Insurance for self-employed sole traders in the UK for 2026-27. Understand Class 2 and Class 4 NI contributions.
Self-employed individuals in the UK pay income tax on their trading profits plus two types of National Insurance: Class 2 (flat rate of approximately £3.45/week) and Class 4 (6% on profits between £12570-£50270 then 2% above that). Total tax burden for a self-employed person earning £50000 is approximately £8700 income tax + £2800 Class 4 NI + £180 Class 2 NI = £11680.
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Key Information
| Parameter | Details |
|---|---|
| Income Tax Rates | 20% / 40% / 45% (same as employed) |
| Class 2 NI | £3.45/week (approx) |
| Class 4 NI | 6% (£12570-£50270) then 2% |
| Payment Deadlines | 31 January and 31 July |
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Use Calculator NowFrequently Asked Questions
How much tax do I pay as self-employed UK?
On £40000 profit: income tax = £5486 (20% on £27430). Class 4 NI = £1646 (6% on £27430). Class 2 NI = £180. Total tax = £7312. Effective rate: 18.3%. Compare to an employee at £40000: income tax £5486 + employee NI £3114 = £8600. Self-employed pay approximately £1300 less due to lower NI rates but must manage their own pension.
When do I pay self-employed tax?
Self-assessment tax returns are due by 31 January following the end of the tax year (5 April). Payments on account: 50% due 31 January and 50% due 31 July based on previous year liability. First year self-employed: you may face a large January bill covering the full year plus first payment on account for the next year. Budget 25-30% of profits for tax throughout the year.
What expenses can self-employed people claim?
Allowable expenses include: office costs (stationery phone internet) travel (business mileage at 45p/mile for first 10000 miles) clothing (uniforms or protective only) staff costs professional fees (accountant lawyer) marketing and advertising insurance and premises costs. Use the simplified expenses flat rate for working from home (£10-26/month depending on hours). Keep all receipts for 6 years.
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Last updated: March 2026