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Self-Employed Tax Calculator

Sole traders pay Income Tax on profit and Class 4 National Insurance at 6% between £12,570 and £50,270, 2% above. Enter turnover and allowable expenses, or just your profit.

Tax year 2026/27 · Estimates, not personal tax advice

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Salary from a job, before tax

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Estimated tax and Class 4 NI

£7,132

on £40,000 of self-employed profit
Self-employed profit£40,000.00
Personal Allowance£12,570.00
Income Tax on earnings and profit−£5,486.00
Class 4 National Insurance−£1,645.80
Total income after tax and NI£32,868.20

Class 2 NI is no longer compulsory. If the bill is over £1,000, HMRC will usually ask for payments on account towards next year too.

Rates and rules used

Tax year 2026/27

Default year 2026/27 (6 April to 5 April). 2025/26 and 2024/25 figures are kept for comparison where the calculator offers a year choice.

Independent site, not affiliated with HMRC. Always check GOV.UK for the latest figures.

How this calculation works

  1. 01Subtract allowable expenses from turnover to find profit.
  2. 02Add any employment income and dividends.
  3. 03Apply the Personal Allowance to earnings and profit first.
  4. 04Tax earnings and profit using your region's bands.
  5. 05Tax dividends on top using UK dividend rates.
  6. 06Add Class 4 NI at 6% and 2% on profit.

Real payroll can differ because tax and NI are worked out per pay period, and your tax code may include adjustments HMRC hasn't told you about. See our methodology.

Class 2 NI

Since April 2024 self-employed people with profits above £6,845 no longer pay Class 2 NI but still get National Insurance credits. Those below can pay voluntarily to protect their State Pension record.

Payments on account

If your Self Assessment bill is over £1,000, HMRC usually asks for two advance payments towards next year's bill, each half of this year's. Your first year's January payment can therefore be around 150% of the bill.

Understanding your self employed tax calculator result

The estimate starts with business profit: turnover less allowable expenses. It then combines that profit with other income to estimate Income Tax and self-employed National Insurance.

Setting aside tax from invoices

Scenario: Enter forecast turnover and allowable expenses, plus salary from any employment. Update the figures as the year progresses.

How to use the result: Use the estimated liability to plan a tax reserve, but keep payments on account in mind: the first large January payment can include an advance towards the next year.

Details to check before relying on the estimate

  • Do not calculate tax on turnover before expenses.
  • Keep evidence for claimed business costs.
  • Losses, capital allowances and basis-period adjustments can need tailored advice.

Putting the estimate into perspective

Keep the tax reserve separate from cash available to spend. An estimate of the year's liability is not a payment calendar and does not by itself show the amount due on each deadline.

Frequently asked questions

How much should I put aside for tax as a sole trader?

Many people set aside 25–30% of profit. Use the calculator with your expected profit for a more precise figure.

Check it on GOV.UK: Income Tax rates and allowances (opens GOV.UK in a new tab) · Self-employed National Insurance rates (opens GOV.UK in a new tab)

Can I use the trading allowance?

If your gross trading income is £1,000 or less, it's tax-free. Above that you can deduct £1,000 instead of actual expenses if that's better.

Check it on GOV.UK: Tax-free allowances on property and trading income (opens GOV.UK in a new tab)

Do I pay tax on turnover or profit?

You pay Income Tax and Class 4 National Insurance on profit after allowable expenses, not on turnover. Keep records so you can show how the profit was worked out.

Check it on GOV.UK: Self-employed National Insurance rates (opens GOV.UK in a new tab) · National Insurance rates and category letters (opens GOV.UK in a new tab)

When must I pay my Self Assessment bill?

The balancing payment and the first payment on account are normally due by 31 January after the tax year ends. HMRC may also ask for a second payment on account in July.

Check it on GOV.UK: Self Assessment tax returns (opens GOV.UK in a new tab)

Related calculators

Related guides

  • Tax for the Self-Employed — How sole traders are taxed in the UK: Income Tax on profit, Class 4 NI, allowable expenses and payments on account.
  • Self Assessment Explained — Who needs to file a Self Assessment tax return, what goes on it, the deadlines for 2026/27 and the penalties for missing them.
  • Tax on Side Hustle Income — When side hustle income becomes taxable, the £1,000 trading allowance, and how platform reporting rules work.