Self-employed tax calculator 2026/27 (UK)
Enter your figures for the tax year to see roughly how much Income Tax and National Insurance you'll owe, and how much to put aside each month. Built for plumbers, electricians, builders and other sole traders.
How it's worked out
Your profit is your turnover minus allowable costs and mileage. Income Tax and Class 4 National Insurance are then charged on that profit using the 2026/27 rates for England, Wales and Northern Ireland.
| Profit band | Income Tax | Class 4 NI |
|---|---|---|
| Up to £12,570 | 0% | 0% |
| £12,571 to £50,270 | 20% | 6% |
| £50,271 to £125,140 | 40% | 2% |
| Over £125,140 | 45% | 2% |
The Personal Allowance shrinks by £1 for every £2 of income over £100,000. This estimate assumes self-employment is your only income and doesn't include Scottish income tax rates, student loan repayments or payments on account.
Common questions
How much tax do I pay if I'm self-employed?
You pay Income Tax on your profit above the £12,570 Personal Allowance: 20% up to £50,270, 40% up to £125,140 and 45% above that. You also pay Class 4 National Insurance: 6% on profit between £12,570 and £50,270, and 2% above.
Is tax worked out on turnover or profit?
On profit, which is your turnover minus allowable business costs. That's why keeping receipts for materials, tools, insurance and mileage matters: for most sole traders, every £100 of costs you record saves £26 to £42 in tax.
How does CIS affect my tax bill?
If you're a construction subcontractor, contractors usually take 20% off the labour part of your invoices under the Construction Industry Scheme. That money has already been paid to HMRC for you, so it comes off your final bill, and you may get a refund.
Do I still pay Class 2 National Insurance?
No. Since April 2024 self-employed people with profits above the Small Profits Threshold no longer pay Class 2 National Insurance, but still get credits towards their State Pension. Below it, you can choose to pay voluntarily to protect your record.