Self Employed Tax Calculator UK
Use our Self Employed Tax Calculator UK to estimate how much Income Tax and National Insurance (NI) you may need to pay on your self-employed profits.
Enter your estimated income and allowable business expenses to calculate your estimated taxable profit and get an idea of your potential tax liability.
At Cheap Accountants In London, we support self-employed individuals with tax returns, bookkeeping, business advice, and ongoing accounting support. Our calculator gives you a quick estimate so you can plan with confidence.
How to Use Our Self Employed Tax Calculator
Here are the steps for using the calculator:
Enter Your Income
Enter your estimated self-employed income for the tax year.
Enter Your Expenses
Add your allowable business expenses. These are deducted from your income to help calculate your taxable profit.
Calculate Your Tax
The calculator will estimate your:
- Taxable profit
- Income Tax
- National Insurance
- Estimated tax liability
Self Employed Tax Rates 2026/27
For the 2026/27 tax year, the standard Personal Allowance is £12,570. Income Tax rates in England are:
- 20% basic rate
- 40% higher rate
- 45% additional rate, subject to the applicable thresholds and your circumstances.
Self-employed people may also pay Class 4 NI:
- 6% on taxable profits over £12,570 up to £50,270
- 2% on taxable profits above £50,270
How Is Self Employed Tax Calculated?
Generally, your self-employed profit is calculated by deducting allowable business expenses from your self-employed income.
Taxable profit = Income − allowable expenses
Income Tax and, where applicable, NI are then calculated based on your taxable profit and other relevant circumstances.
For Example
If your self-employed income is £40,000 and your allowable expenses are £5,000, then:
£40,000 − £5,000 = £35,000 taxable profit
The calculator can then give an estimate of the Income Tax and NI that may be due.
Self Assessment Tax Deadline
For the 2025/26 tax year, the online Self Assessment return and any tax due are due by 31 January 2027.
Note that this calculator provides an estimate only. Your actual tax liability may vary depending on your allowable expenses, tax reliefs, other income, allowances and personal circumstances.
Need Help With Self Employed Tax?
AT CAIL, our London accountants can help self-employed individuals with self-assessment tax returns, bookkeeping, and tax planning. So if you need help with your self-employed tax, contact us today!
Frequently Asked Questions
What is a Self Employed Tax Calculator UK?
It is an online tool that estimates the Income Tax and NI you may owe based on your self-employed profits.
Do I need to register as self-employed?
Typically, you need to register for Self Assessment as a sole trader if you earn more than £1,000 in gross trading income in a tax year, unless an exception applies. Also, you can register voluntarily if your circumstances require it.
How much can a self-employed person earn before paying tax?
The standard Personal Allowance is £12,570 for the 2026/27 tax year. However, your allowance can be reduced if your income is above £100,000.
Do self-employed people pay National Insurance?
Self-employed people may need to pay Class 4 NI depending on their profits. For 2026/27, Class 4 applies at 6% above £12,570 up to £50,270 and 2% above £50,270.
Can I deduct business expenses?
You can deduct allowable business expenses when calculating your taxable profit, provided they meet the relevant HMRC rules.
Do I pay tax on my turnover or profit?
Self-employed Income Tax is generally based on your taxable profit, rather than your total turnover. Your allowable business expenses can reduce the profit on which tax is calculated.
Does the calculator include payments on account?
A basic self employed tax calculator UK may estimate your tax liability, but payments on account are separate amounts that HMRC may require towards your next tax bill. So, your actual Self Assessment bill can be different from the tax estimate shown by the calculator.
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