Answers · UK 2025/26

How much tax and National Insurance do I pay on £100,000 self-employed profit?

On £100,000 of self-employed taxable profit in 2026/27, you pay £27,432 Income Tax and £3,256.60 Class 4 National Insurance, keeping £69,311.40 after tax and NI. At exactly £100,000 your Personal Allowance is not yet reduced, but £1 more of profit starts the taper.

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

Full answer

For a self-employed sole trader with £100,000 of taxable profit in 2026/27, the first £12,570 is covered by the Personal Allowance, the next £37,700 is taxed at 20% basic rate (£7,540), and the remaining £49,730 is taxed at 40% higher rate (£19,892), giving total Income Tax of £27,432. Class 4 National Insurance is charged at 6% on profits between the £12,570 Lower Profits Limit and the £50,270 Upper Profits Limit (£2,262), plus 2% on the £49,730 above that limit (£994.60), giving total Class 4 National Insurance of £3,256.60. Total deductions leave £69,311.40 after tax and National Insurance. £100,000 is a critical threshold: adjusted net income (broadly your taxable profit) above this level starts tapering away your Personal Allowance at a rate of £1 for every £2 earned, so profit of £100,001 already begins losing Personal Allowance, creating an effective marginal rate of around 62% once Class 4 National Insurance is included, up to £125,140 where the allowance is fully gone. Many self-employed people at this level increase pension contributions to bring adjusted net income back to £100,000 or below, which both restores the Personal Allowance and attracts tax relief. Payments on Account -- two advance instalments toward next year's Self Assessment bill, due 31 January and 31 July -- can be substantial at this income level and should be budgeted for well in advance.