Self-Employed Tax Calculator
Estimate your UK income tax and National Insurance for the 2025/26 tax year in under a minute. Real HMRC bands. No signup, no email collection.
Your income
The maths, in plain English
- Personal Allowance of £12,570 — reduced by £1 for every £2 you earn above £100,000 (fully gone at £125,140)
- Income tax: 20% basic rate from £12,571 to £50,270, 40% higher from £50,271 to £125,140, 45% additional above
- Class 4 NI: 6% on profits between £12,570 and £50,270, then 2% above £50,270
- Class 2 NI: not included — voluntary from April 2024 onwards
- Doesn't include Student Loan, dividends, Capital Gains, Marriage Allowance, or other reliefs
- Doesn't include payments on account — your actual cashflow may include extra payments due 31 Jan and 31 July
File your Self Assessment for £79
One UK-qualified accountant, fixed fee, filed in 24 hours. We catch every legitimate deduction your DIY return would miss.
What does "self-employed" mean for tax?
You're self-employed in the UK if you run a business for yourself and take responsibility for its success or failure. HMRC treats sole traders, freelancers, contractors (operating as an individual not a Ltd) and most CIS sub-contractors as self-employed.
Self-employed income is taxed via Self Assessment — you pay income tax on profit (income minus allowable expenses) plus Class 4 National Insurance on profit above £12,570.
- Sole traders / freelancers · sole-name business
- Side-gig income above the £1,000 trading allowance
- CIS sub-contractors
- Couriers, drivers, delivery workers (Uber, Deliveroo, Bolt)
- eBay / Etsy / Vinted sellers above the trading threshold
How is self-employed tax calculated?
Two taxes stack on top of each other. Both run on profit, not gross turnover:
| Profit band (2025/26) | Income tax | Class 4 NI | Combined |
|---|---|---|---|
| £0 – £12,570 (Personal Allowance) | 0% | 0% | 0% |
| £12,571 – £50,270 (basic rate) | 20% | 6% | 26% |
| £50,271 – £125,140 (higher rate) | 40% | 2% | 42% |
| £125,140+ (additional rate) | 45% | 2% | 47% |
The Personal Allowance starts to taper above £100,000 (you lose £1 of allowance per £2 of income), giving an effective 60% marginal rate between £100k and £125,140.
Key deadlines for self-employed Self Assessment
Tax year runs 6 April to 5 April. For the 2025/26 tax year, key dates:
- 5 October 2026 — register for Self Assessment if you became self-employed in 2025/26
- 31 October 2026 — paper return deadline (almost no-one uses this)
- 31 January 2027 — online return + balancing payment + first Payment on Account due
- 31 July 2027 — second Payment on Account due
Miss the 31 January deadline and you'll face a £100 instant fine even if you owe £0 — penalties grow quickly from there.
How to reduce your self-employed tax bill (legally)
- Claim every allowable expense — mileage at 45p/mile, use-of-home, equipment, training, professional subscriptions, software
- Pension contributions — personal contributions get tax relief at your marginal rate (up to £60k/year)
- Annual Investment Allowance — full deduction on equipment up to £1m/year
- Time large expenses — buy equipment before 5 April to use this year's allowances
- Consider going Ltd — typically saves 5–15% in tax above £50k profit via salary/dividend split
- Use the £1,000 trading allowance — alternative to claiming actual expenses if costs are low
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