Self-Employed Tax Calculator UK
Calculate your Income Tax, Class 2 and Class 4 National Insurance for the 2025/26 tax year. See exactly what you'll owe HMRC.
Your Details
Income minus allowable expenses
If you work under CIS, enter tax deducted by contractors
2025/26 Tax Rates
Income Tax:
• 0% up to £12,570
• 20% on £12,571 - £50,270
• 40% on £50,271 - £125,140
• 45% above £125,140
National Insurance:
• Class 2: £3.45/week (£179.40/year)
• Class 4: 9% on £12,570 - £50,270
• Class 4: 2% above £50,270
Your Tax Bill
Total Tax Owed
£8134.10
20.3% of your profit
Amount to Pay
£8134.10
Net Income After Tax
£31865.90
Tax Breakdown
💰 Set Money Aside
Save 20% of every job for tax. Open a separate savings account and transfer it immediately.
📅 Payment Deadlines
31 January: Balancing payment + Payment on Account #1
31 July: Payment on Account #2
📝 Keep Records
Save all receipts for 5 years minimum. Track every business expense to reduce your tax bill legally.
🧾 Self Assessment
File by 31 January online (31 October for paper). Late filing = £100 fine minimum.
How Self-Employed Tax Works in the UK (2025/26)
If you're self-employed as a plumber, electrician, builder, or any other UK trade, you pay tax differently than employees. This calculator shows you exactly what you'll owe HMRC based on your profit, including Income Tax and National Insurance contributions.
What Tax Do Self-Employed People Pay?
1. Income Tax (on profits above £12,570)
- • Personal Allowance: £12,570 (tax-free)
- • Basic rate (20%): £12,571 to £50,270
- • Higher rate (40%): £50,271 to £125,140
- • Additional rate (45%): Over £125,140
2. Class 2 National Insurance
£3.45 per week if your profits are £12,570 or more per year (£179.40 annually). Voluntary if profits are below this threshold.
3. Class 4 National Insurance
- • 9% on profits between £12,570 and £50,270
- • 2% on profits above £50,270
How CIS Deductions Reduce Your Tax Bill
If you work under the Construction Industry Scheme (CIS), your contractor deducts tax at source (20% or 30%). These deductions count as payments towards your annual tax bill.
Example: CIS Subcontractor
- • Total profit: £40,000
- • CIS deductions: £6,000 (20% × £30,000 labour)
- • Total tax owed: £7,667 (Income Tax + NI)
- • Amount to pay: £1,667 (already paid £6,000 via CIS)
- • You get credit for the CIS deductions when filing your Self Assessment
What Counts as Profit?
Your taxable profit is your total income minus allowable business expenses:
✅ Allowable Expenses
- • Materials and stock
- • Van running costs
- • Tools and equipment
- • Insurance (liability, van)
- • Accountant fees
- • Rent for workspace
- • Phone and internet (business %)
- • Marketing and advertising
- • Professional subscriptions
❌ Not Allowable
- • Your own salary/drawings
- • Personal expenses
- • Clothes (unless protective)
- • Fines and penalties
- • Business entertainment
- • Personal phone calls
- • Non-business travel
When Do You Pay?
Payment Schedule
- 31 January: Payment on Account #1 (50% of last year's bill) + balancing payment for previous tax year
- 31 July: Payment on Account #2 (50% of last year's bill)
First year self-employed? You only pay once (31 January). Payments on Account start in your second year.
Common Tax Mistakes to Avoid
1. Not Setting Money Aside
Save 30-35% of your profit for tax. Don't spend it thinking it's all yours. Set up a separate savings account for tax.
2. Missing Allowable Expenses
Keep receipts for EVERYTHING. Van costs, tools, phone bills, insurance - it all adds up. Missing expenses = paying more tax.
3. Forgetting Payment on Account
From year 2 onwards, you pay twice a year. Many tradespeople get caught out by the July payment they forgot about.
4. Not Claiming CIS Tax Back
If your contractor deducted CIS tax, you MUST file a Self Assessment to claim credit. Otherwise you've overpaid.
Sole Trader vs Limited Company Tax
Once your profit exceeds £50,000-£60,000, a limited company often saves you money on tax. Here's why:
| Structure | Tax on £60,000 | Take Home |
|---|---|---|
| Sole Trader | £14,852 | £45,148 |
| Limited Company | £11,925 | £48,075 |
Limited company uses £12,570 salary + £47,430 dividend strategy. Accountant fees not included.
Related Calculators
CIS Tax Calculator
Calculate net pay after 20% or 30% CIS deductions
Profit Margin Calculator
Work out gross profit, net profit, and markup percentage
Helpful Resources
- • Complete CIS Tax Guide for Subcontractors 2026
- • Sole Trader vs Limited Company Guide 2026
- • UK Trades Tax Deduction Checklist 2026
- • End of Tax Year Checklist for UK Trades
⚠️ Not Tax or Accounting Advice
This guide is for informational purposes only and does not constitute tax advice, accounting advice, or professional financial services. Tax laws, allowances, and HMRC requirements change frequently.
Before making any tax decisions or filing returns: Consult a qualified accountant or tax advisor who can review your specific circumstances. What's mentioned here may not apply to your situation, and regulations may have changed since publication.
Official source: HMRC (gov.uk/hmrc)
Turn Tax Estimates into a Simple Routine
Use this calculator to estimate what you'll owe, then set aside money regularly so the January tax bill doesn't come as a shock.
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