Calculate your income tax, Class 2 and Class 4 National Insurance as a self-employed sole trader. Updated for 2026/27.
This calculator estimates the total tax and National Insurance contributions (NICs) payable by a UK sole trader or self-employed individual. It covers Income Tax across all bands and both Class 2 and Class 4 NICs.
Note: Based on 2026/27 HMRC rates. The personal allowance is £12,570. Class 4 NICs apply at 6% on profits between £12,570 and £50,270, and 2% above.
Class 2 NIC (£3.50/week) applies if profits exceed £12,570. Class 4 NIC is 6% on profits between £12,570–£50,270 and 2% above. The personal allowance tapers above £100,000.
| Class 2 (if profit > £12,570) | £3.50/week |
| Class 4 (£12,570–£50,270) | 6% |
| Class 4 (above £50,270) | 2% |
How take-home and tax change as income grows (no expenses, no other income)
Sole traders must file their Self Assessment tax return by 31 January following the end of the tax year. Online filing for 2026/27 is due 31 January 2027. Late filing incurs a £100 penalty.
If your tax bill exceeds £1,000, you must make two payments on account (31 Jan and 31 Jul). Each is 50% of the previous year’s tax bill, which can create a large initial payment.
You can deduct allowable business expenses from your income before calculating tax. These include office costs, travel, equipment, marketing, and professional fees used wholly for business.