Answers · UK 2025/26

How much tax and National Insurance does a self-employed plumber pay on £36,000 profit?

A self-employed plumber with £36,000 taxable profit in 2026/27 pays £4,686 Income Tax and £1,405.80 Class 4 National Insurance, keeping £29,908.20 after tax and NI. There is no separate Class 2 charge for most self-employed people, since it was abolished from April 2024.

Last updated: 3 July 2026Last reviewed: 3 July 2026How we verify

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Self-employed plumbers pay Income Tax on their trading profit -- income minus allowable business expenses such as materials, van costs, tools, public liability insurance and Gas Safe or other trade registration fees -- using the same tax bands as employees, but pay Class 4 National Insurance rather than employee Class 1 NI, typically settling their bill through Self Assessment. On £36,000 taxable profit for 2026/27: after the £12,570 Personal Allowance, £23,430 is taxable, entirely within the 20% basic rate band, giving £4,686 Income Tax. Class 4 National Insurance is charged at 6% on profits between the £12,570 Lower Profits Limit and the £50,270 Upper Profits Limit, so 6% of £23,430 is £1,405.80. Class 2 National Insurance was abolished for most self-employed people from April 2024, though those with profits below the £7,105 Small Profits Threshold can still pay it voluntarily to protect their State Pension record -- not relevant at £36,000 profit. Total deductions of £6,091.80 leave £29,908.20 after tax and National Insurance. Many self-employed plumbers register for VAT once turnover (not profit) exceeds the £90,000 registration threshold, which is a separate consideration from Income Tax and applies to the whole business, not personal earnings. A self-employed plumber should also budget for a January payment on account toward the following year's tax bill if their liability exceeds £1,000, and keep detailed records of van, tool and material costs to correctly calculate the £36,000 profit figure used in this example.