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Sole Trader Tax Calculator UK

Enter your values below to get the result first, then scroll for the full explanation and guidance.

Step 1 • Add values

Use the calculator

Enter your values below to generate an instant result. You can update the inputs at any time to compare different scenarios.

Example: GBP 60,000 turnover less GBP 10,000 allowable expenses gives GBP 50,000 trading profit. Income Tax and Class 4 NI are then calculated separately.

Results refresh instantly as values change.

Estimated annual Income Tax and Class 4 NI

£9,731.802026/27 sole-trader illustration

Estimated annual Income Tax and Class 4 NI: £9,731.80 (2026/27 sole-trader illustration)

Trading profit is turnover less the selected allowable deduction. Income Tax and Class 4 NI are calculated separately on that profit.

Profit and tax breakdown

Trading profit is turnover less the selected allowable deduction. Income Tax and Class 4 NI are calculated separately on that profit.

Result snapshot

A quick visual read of the values behind this result.

Annual turnover£60,000.00
Allowable expenses£10,000.00
Taxable trading profit£50,000.00
Income Tax£7,486.00
Class 4 National Insurance£2,245.80
Profit after estimated tax and NI£40,268.20

Recommended next checks

  • →Check expenses or trading-allowance eligibility before filing Self Assessment. Other income, losses and payments on account can change what you owe.
Annual turnover
£60,000.00
Allowable expenses
£10,000.00
Taxable trading profit
£50,000.00
Income Tax
£7,486.00
Class 4 National Insurance
£2,245.80
Profit after estimated tax and NI
£40,268.20

One UK-resident sole trader with no other taxable income, losses, pension relief or special adjustments. The £1,000 trading allowance cannot be combined with expenses and may be unavailable in some circumstances. No mandatory Class 2 NI is included for 2026/27; voluntary Class 2 and payments on account are excluded.

Try different values to compare results.

Enter annual trading turnover and either allowable expenses or the eligible GBP 1,000 trading allowance. The tool estimates taxable profit, 2026/27 Income Tax and Class 4 NI; it does not calculate Self Assessment payments on account.

Restricted scope stated

Applicable period shown

Excluded claim or payroll factors disclosed

Table of Contents

5

About Sole Trader Tax Calculator UK

Sole Trader Tax Calculator UK helps you work through the main numbers for this topic quickly with a simple input flow and an instant result.

Use the calculator result as a practical starting point, then review the explanation and assumptions on the page if you want more context.

How sole-trader tax is estimated

Taxable trading profit equals turnover less allowable expenses, or less the trading allowance if eligible and selected. The standard Personal Allowance and applicable UK or Scottish Income Tax bands are applied to profit, followed by separate Class 4 National Insurance. Class 2 NI is generally treated as paid at or above the small profits threshold without a mandatory payment.

Formula explained

Sole-trader Income Tax and Class 4 NI

Estimate 2026/27 Income Tax and Class 4 National Insurance on a sole trader's taxable trading profit after eligible expenses or the trading allowance.

Formula

Trading profit = turnover - eligible expenses or trading allowance; total = 2026/27 Income Tax on profit + Class 4 NI on profit

How the result is built

1Choose allowable expenses or the eligible trading allowance, not both.
2Calculate taxable trading profit and apply the relevant Income Tax bands.
3Calculate Class 4 NI separately; other income and payments on account are excluded.

Example

Example: GBP 60,000 turnover less GBP 10,000 allowable expenses gives GBP 50,000 trading profit. Income Tax and Class 4 NI are then calculated separately.

Assumptions

  • One UK-resident sole trader in the 2026/27 tax year with no other taxable income, losses, reliefs or pension contributions.
  • The trading allowance is used instead of expenses, never together; check eligibility before choosing it.
  • Class 4 NI uses 6% above GBP 12,570 to GBP 50,270 and 2% above that. No mandatory Class 2 charge is added.
  • Payments on account, student loans and voluntary Class 2 contributions are excluded.

Source basis

  • HMRC: self-employed NI rates, trading allowance, 2026/27 Income Tax bands

Trust and notes

Assumptions and important notes

This calculator is designed to give a fast estimate using the method shown on the page. Results are most useful when your inputs are accurate and the tool matches your situation.

Use the result as guidance rather than a final diagnosis or professional decision. If the result could affect health, legal, financial, or compliance decisions, verify it with a qualified source where appropriate.

  • One UK-resident sole trader in the 2026/27 tax year with no other taxable income, losses, reliefs or pension contributions.
  • The trading allowance is used instead of expenses, never together; check eligibility before choosing it.
  • Class 4 NI uses 6% above GBP 12,570 to GBP 50,270 and 2% above that. No mandatory Class 2 charge is added.
  • Payments on account, student loans and voluntary Class 2 contributions are excluded.

Method

Sole-trader Income Tax and Class 4 NI

Last reviewed

October 13, 2026