Self-Employed Tax Calculator UK
Estimate how much Income Tax and National Insurance you may pay on your self-employed income. Choose your tax year, enter your business income and expenses, and see an estimated breakdown of your tax bill.
Calculations are based on standard UK tax rules and are intended as a guide only.
Calculate your self-employed tax
Estimate Income Tax and self-employed Class 4 National Insurance for 2025/26.
Your total self-employed business income before expenses.
Business expenses you are entitled to deduct for tax purposes.
Some individuals can deduct the £1,000 trading allowance instead of claiming actual business expenses. You cannot normally claim both against the same income.
MoneyCalcs UK provides estimates for general information only. Results are not financial, tax or legal advice and may not match your final HMRC calculation. Tax depends on your individual circumstances. Check your figures against GOV.UK, HMRC or an appropriately qualified professional where necessary.
Privacy: figures entered into this calculator stay in your browser and are not sent to MoneyCalcs UK.
What this calculator includes
- Self-employed trading profit
- Optional employment income
- Standard Personal Allowance
- Income Tax
- Scottish Income Tax bands where selected
- Class 4 National Insurance
- Basic estimate of payments on account
What this calculator does not currently include
- Savings income
- Dividend income
- Property income
- Capital Gains Tax
- Student loan repayments
- Pension contribution tax relief
- Marriage Allowance
- Blind Person's Allowance
- Trading loss relief
- CIS deductions
- Multiple self-employed businesses
- Partnership income
- High Income Child Benefit Charge
- Special National Insurance situations
- Employee National Insurance calculations
- Unusual tax adjustments or reliefs
If any of these apply to you, your actual tax position may differ.
This calculator assumes you are liable to standard Class 4 National Insurance. Special exemptions or adjustments may apply in some circumstances, including certain age or National Insurance situations.
How does the UK self-employed tax calculator work?
Tax for the self-employed is generally calculated on your taxable profits rather than your turnover. You start with everything your business invoiced or received, then reduce it by the expenses you are allowed to deduct for tax purposes — or, if you are eligible and it works out better, by the flat £1,000 trading allowance instead.
The resulting profit is added to any employment income to work out your Personal Allowance and which Income Tax bands apply. Class 4 National Insurance is then charged separately on the self-employed profit alone.
What tax does a self-employed person pay?
Income Tax is charged on your taxable income above your Personal Allowance, at progressive rates. In England, Wales and Northern Ireland that means 20%, then 40%, then 45%. Scotland has more bands, starting at 19% and rising to 48%.
Class 4 National Insurance is a separate charge on self-employed profits: nothing up to £12,570, 6% between £12,570 and £50,270, and 2% above that. Class 2 National Insurance is normally treated as paid where profits are above the Small Profits Threshold, so this calculator does not add a compulsory Class 2 charge.
What is the difference between 2025/26 and 2026/27?
If you are completing your 2025/26 Self Assessment tax return, select 2025/26 so the calculator uses the rates and thresholds for the year you are reporting. Select 2026/27 to estimate your current-year position — useful for budgeting while the tax year is still running. The Personal Allowance and Class 4 thresholds are the same in both years; the Scottish bands and the Class 2 figures differ.
How much should I put aside for self-employed tax?
Because self-employed tax is paid in lump sums rather than out of each payslip, it helps to reserve money as you earn it. The calculator divides the estimated amount you would owe through Self Assessment by twelve to give an approximate monthly reserve. It is a budgeting guide only — your income may vary through the year, and HMRC's payment dates are not monthly.
What are payments on account?
Payments on account are two advance payments towards your next Self Assessment bill, normally each half of the previous year's amount and usually due on 31 January and 31 July. They typically apply where the amount you owe through Self Assessment is £1,000 or more and less than 80% of your tax was already collected at source, such as through PAYE. The figures here are a simple estimate — your HMRC statement determines what is actually due.
Frequently asked questions
Official sources
- Income Tax rates and allowances (GOV.UK)
- Self-employed National Insurance rates (GOV.UK)
- National Insurance rates and allowances (GOV.UK)
- Scottish Income Tax (GOV.UK)
- Tax-free allowances on property and trading income (GOV.UK)
- Understand your Self Assessment bill: payments on account (GOV.UK)
MoneyCalcs UK is not affiliated with or endorsed by HMRC or the UK Government.
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