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Self-employment tax estimator
Estimate Income Tax and Class 4 National Insurance on a profit figure.
Illustrative result
£4,011.80 estimated tax and Class 4 National Insurance
2026 to 2027 · England, Wales and Northern Ireland
- Taxable profit used
- £28,000.00
- Income Tax
- £3,086.00
- Class 4 National Insurance
- £925.80
- Combined estimate
- £4,011.80
- Profit after those amounts
- £23,988.20
Assumptions
- You cannot use the trading allowance and deduct expenses for the same income. The switch chooses one.
- Class 2 is voluntary in the current published rules and is not added unless a later screen says you have chosen to pay it.
- Payments on account, student loans through Self Assessment and the cash basis are not included.
- Plan 2 interest is a variable rate. No single interest rate is applied unless you enter an assumption.
- Future tax years after 2026/27 are not published here. Forecasts keep the selected year's rules as an assumption and say so.
Questions
Is this a Self Assessment return?
No. It estimates tax and Class 4 National Insurance on one profit figure.
Use this in your own plan
The result stays in your browser. Create an Aldoraun account if you want to keep a budget, accounts and a cashflow forecast.
Related calculators
Estimates only. Tax and repayment rules can change, and this is not financial, tax or pension advice.
Estimated tax and Class 4 National Insurance£4,011.80See breakdown