Calculate your self-employed tax.

A self-employed sole trader in the UK pays income tax at 20% on profit between £12,571 and £50,270, 40% between £50,271 and £125,140, and 45% above that. They also pay Class 4 National Insurance at 6% on profit between £12,570 and £50,270, and 2% above £50,270. The first £12,570 is tax-free (the Personal Allowance). For a sole trader with £40,000 profit in 2026/27, income tax and Class 4 NI come to about £7,132.

The Personal Allowance for self-employed people in the UK is the same as for employees: £12,570 in 2026/27. You pay no income tax on the first £12,570 of profit. The allowance shrinks by £1 for every £2 of income over £100,000, so it is gone completely at £125,140.

Class 4 National Insurance is the NI charge for self-employed people in the UK. In 2026/27, you pay 6% on profits between £12,570 and £50,270, and 2% on profits above £50,270. Since 6 April 2024 you no longer have to pay Class 2 NI. Class 4 NI is calculated automatically when you file your Self Assessment return.

A sole trader in Ireland pays income tax at 20% on profit up to €44,000 (single person) and 40% above that, less €4,000 of tax credits (Personal Tax Credit €2,000 plus Earned Income Tax Credit €2,000). They also pay USC at 0.5% to 8%, with 11% on self-employed income over €100,000, and Class S PRSI. Class S is 4.2% until 30 September 2026 and 4.35% from 1 October 2026, so 2026 self-assessment uses a blended 4.2375% (minimum €650). For a sole trader with €50,000 profit in 2026, income tax, USC and PRSI come to about €10,352.

Profit for tax purposes is your gross income from self-employment minus your allowable business expenses. You are taxed on profit, not on turnover. Allowable expenses include tools and materials, van running costs (business proportion), work clothing and PPE, phone (business proportion), insurance, and accountant fees. Personal expenses cannot be claimed.

UK sole traders pay income tax and National Insurance via Self Assessment. The main deadline is 31 January - this is when you must file your online tax return and pay your bill for the previous tax year. If your bill exceeds £1,000, HMRC also requires Payments on Account: a first payment on 31 January and a second on 31 July.

Irish sole traders pay income tax, USC, and PRSI via the self-assessment system. The main deadline is 31 October each year - you must file your Form 11 on ROS, pay any balance owed on the previous year, and pay preliminary tax for the current year. Filing and paying through ROS gives you a later deadline, which Revenue sets each year: Wednesday 18 November 2026 for returns due on 31 October 2026.