Self-Employed Tax Calculator
Estimate the Income Tax and Class 4 National Insurance you pay on your self-employed profit, and what you keep, for 2025/26.
income after expenses
Income Tax plus Class 4 NI, England, Wales & Northern Ireland.
Estimated take-home
£32,868
17.8% of profit in tax & NI
- Income Tax
- − £5,486
- Class 4 National Insurance
- − £1,646
- Total tax & NI
- − £7,132
- Take-home
- £32,868
How is self-employed tax worked out?
As a sole trader you pay Income Tax and National Insurance on your profit, which is your income after allowable business expenses. Income Tax uses the same bands and Personal Allowance as employees: nothing up to £12,570, then 20%, 40% and 45%.
On top of that you pay Class 4 National Insurance, charged at 6% on profits between £12,570 and £50,270 and 2% above that for 2025/26. Class 2 National Insurance is no longer charged for most people, though you can pay it voluntarily to protect your State Pension record.
Payments on account and setting money aside
Self-employed tax is paid through Self Assessment, usually by 31 January, with payments on account often due in January and July towards the following year. Because tax is not deducted at source, it is wise to set aside a portion of every invoice.
A rough rule is to save around 25 to 30% of your profit for tax and NI, though higher earners should set aside more. This calculator gives you the figure to plan around.
Worked example
On a £40,000 profit you pay about £5,486 in Income Tax and £1,646 in Class 4 National Insurance, a total of roughly £7,132.
That leaves an estimated take-home of about £32,868 before any pension contributions or student loan.
Please note: Estimates use 2025/26 rates for England, Wales and Northern Ireland (Income Tax plus Class 4 NI). Not tax advice.
Frequently asked questions
Is this profit or turnover?
Enter your profit, which is your income after allowable business expenses. Tax and NI are charged on profit, not on total turnover.
Does it include Class 2 NI?
For 2025/26 most self-employed people no longer pay Class 2. It shows Income Tax and Class 4 NI, which are the main charges on profit.
What about student loans or pension?
This focuses on tax and Class 4 NI. Student loan repayments and pension contributions are separate and would reduce your take-home further.
When do I pay?
Through Self Assessment, normally by 31 January, often with payments on account in January and July towards next year's bill.
Is this exact?
It is a close estimate using standard rates. Your actual bill depends on your full circumstances, so keep records and consider an accountant.
Figures last reviewed on 13 August 2025.
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