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Self-Employed Tax Calculator UK
Estimate your self-employed profit, Income Tax, Class 4 National Insurance and take-home income for the 2026/27 tax year.
2026/27 tax year
Income Tax + Class 4 NI
England, Wales & NI bands
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Calculate your self-employed tax
Enter your income, expenses and any other taxable income. The result updates automatically.
Total business income before expenses.
Costs you can deduct from business income.
Employment, rental or other taxable income.
Used for annual allowance warning only in this simple estimate.
Scottish income tax bands differ.
Uses 2026/27 assumptions.
How to use this calculator
- Enter your self-employed income before expenses.
- Add allowable business expenses to estimate taxable profit.
- Add any other taxable income if relevant.
- Review estimated Income Tax, Class 4 National Insurance and take-home profit.
What your result means
The take-home figure is your estimated self-employed profit after Income Tax and Class 4 National Insurance. It does not include student loan repayments, payments on account, VAT, corporation tax, benefits, child benefit charge or accountant adjustments.
Use this as a planning estimate, not a Self Assessment replacement.
Important: Scottish income tax bands are different. If you select Scotland, the calculator keeps the England/Wales/NI estimate but shows a warning.
Ready to plan your tax money?
Use your estimate to set aside tax monthly and avoid being caught short when Self Assessment is due.
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How self-employed tax works
Self-employed tax starts with profit. Profit is your business income minus allowable expenses. That profit is then combined with other taxable income to estimate Income Tax.
The calculator uses the standard Personal Allowance and applies the basic, higher and additional Income Tax bands for England, Wales and Northern Ireland. If total income rises above £100,000, the Personal Allowance is gradually reduced.
Class 4 National Insurance is calculated separately on self-employed profits. It is not calculated on other employment or investment income.
A pension contribution can affect real tax planning, but this simple calculator only uses the pension input to warn if contributions exceed the standard annual allowance. Speak to a tax adviser if pension relief is central to your calculation.
What affects your self-employed tax result
- Profit: income after allowable expenses drives the main calculation.
- Other income: extra taxable income can push more profit into higher tax bands.
- Personal Allowance: the standard allowance can be reduced once adjusted income exceeds £100,000.
- Class 4 NI: National Insurance is based on self-employed profit bands, not total income.
- Region: Scottish taxpayers use different income tax bands.
Self-employed tax formula
The calculator follows this simplified structure.
profit = income - allowable_expenses
adjusted_income = profit + other_taxable_income
personal_allowance = £12,570, reduced above £100,000
taxable_income = adjusted_income - personal_allowance
income_tax = 20% basic band + 40% higher band + 45% additional band
class_4_NI = 6% on profits from £12,570 to £50,270
+ 2% on profits above £50,270
take_home = profit - income_tax - class_4_NI2026/27 quick reference
Figures shown are for the 2026/27 tax year.
| Item | 2026/27 figure | Used for |
|---|---|---|
| Personal Allowance | £12,570 | Income before tax normally starts. |
| Basic-rate band | 20% on taxable income up to £37,700 | First income tax band after allowance. |
| Higher rate | 40% above the basic band up to the additional-rate threshold | Higher income tax estimate. |
| Additional rate | 45% above £125,140 | Additional-rate income tax estimate. |
| Class 4 National Insurance | 6% from £12,570 to £50,270, then 2% | Self-employed National Insurance estimate. |
Self-employed tax calculator FAQs
How is self-employed tax calculated?
It starts with profit, which is income minus allowable expenses. Income Tax and Class 4 National Insurance are then estimated from that profit and your other taxable income.
Does this include Class 2 National Insurance?
No. This calculator focuses on Income Tax and Class 4 National Insurance. Class 2 rules can still matter for your National Insurance record.
Can I deduct expenses?
Yes, allowable business expenses reduce taxable profit. Enter your expenses separately so the calculator can estimate your profit first.
Does this work for Scotland?
The calculation uses England, Wales and Northern Ireland bands. Scottish taxpayers should treat the result as a rough estimate only.
Is this exact enough for Self Assessment?
No. It is a planning estimate, not a full Self Assessment calculation or tax advice.
Key terms used in this calculator
These glossary terms help explain the tax and planning concepts behind the estimate.