Self-employed tax calculator.
Enter your profit and see the income tax and Class 4 National Insurance to set aside, and what you keep.
Work out what to set aside
Change the numbers and the result updates instantly.
How it is worked out
Income tax uses a personal allowance of £12,570, 20% on the next £37,700, 40% up to £125,140 and 45% above that. The personal allowance reduces once total income passes £100,000.
Class 4 National Insurance is 6% on profits between £12,570 and £50,270 and 2% above that. Class 2 is no longer payable for most self-employed people.
About this calculator
What the self-employed tax calculator tells you
This calculator estimates the income tax and Class 4 National Insurance you may owe on your self-employed profit, and how much of it you keep. Enter your turnover and allowable expenses (or your profit), add any other income such as a salary, and you get a clear estimate of your Self Assessment bill before you file.
Figures shown are for the 2026/27 tax year (6 April 2026 to 5 April 2027) for taxpayers in England, Wales and Northern Ireland. Scottish income tax bands differ.
Quick answer
On £30,000 of self-employed profit and no other income, you would owe about £3,486 income tax and £1,046 Class 4 National Insurance, a total of roughly £4,532. You would keep about £25,468.
How self-employed tax is worked out
Your taxable profit is your turnover minus allowable business expenses. If your turnover is under £1,000 you may not need to report it at all, and if you have very low costs you can claim the £1,000 trading allowance instead of actual expenses. From your profit, the first £12,570 is covered by your Personal Allowance. The rest is taxed in bands, and Class 4 National Insurance is charged separately on profits above the same £12,570 threshold.
| Band | Taxable income | Rate |
|---|---|---|
| Personal Allowance | Up to £12,570 | 0% |
| Basic rate | £12,571 to £50,270 | 20% |
| Higher rate | £50,271 to £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
| Class 4 NI | £12,570 to £50,270 | 6% |
| Class 4 NI | Over £50,270 | 2% |
The Personal Allowance is reduced by £1 for every £2 of income above £100,000, which is why the effective rate between £100,000 and £125,140 is so high. Class 2 National Insurance is no longer a compulsory charge for most self-employed people, so the calculator focuses on Class 4.
Worked examples for 2026/27
| Profit | Income tax | Class 4 NI | Total | You keep |
|---|---|---|---|---|
| £20,000 | £1,486 | £446 | £1,932 | £18,068 |
| £30,000 | £3,486 | £1,046 | £4,532 | £25,468 |
| £50,000 | £7,486 | £2,246 | £9,732 | £40,268 |
| £80,000 | £19,432 | £2,857 | £22,289 | £57,711 |
These examples assume no other income and no pension or Gift Aid relief. Real bills also depend on payments on account, which are covered below.
How to use the calculator
- Enter your total business income for the tax year.
- Add your allowable expenses, or choose the trading allowance if that gives a better result.
- Include any other taxable income, such as employment pay.
- Read the split between income tax, National Insurance and what you keep, then set aside the tax as you earn.
Payments on account and deadlines
If your Self Assessment bill is over £1,000, HMRC normally asks for two payments on account towards next year. The first is due on 31 January with your balancing payment, and the second on 31 July. This means your first bill after starting out can feel like 150% of your tax. Our estimate shows the liability for the year, so remember to budget for the advance payments too. The online filing deadline is 31 January following the end of the tax year.
Assumptions and limits
- Uses 2026/27 rates for England, Wales and Northern Ireland.
- Does not include student loan repayments, the High Income Child Benefit Charge or dividend and savings income.
- Treats profit as taxable profit after expenses and capital allowances.
- Is an estimate only. Your final liability depends on your full tax return.
Frequently asked questions
How much tax do I pay on £30,000 self-employed?
Around £3,486 income tax and £1,046 Class 4 National Insurance for 2026/27, about £4,532 in total, if you have no other income.
Do I pay National Insurance as a sole trader?
Yes, you pay Class 4 National Insurance at 6% on profits between £12,570 and £50,270 and 2% above that.
Can I reduce my bill?
Yes. Claim every allowable expense, use capital allowances where they apply, pay into a pension and make Gift Aid donations. Our accountants will check you claim everything you are entitled to.
Authorised and regulated
Is Cheap Tax Returns authorised and regulated? Yes.
Your return is prepared by qualified UK accountants holding qualifications from the leading accountancy bodies: ICAEW, ACCA and AAT. We are also on the ICAEW approved employers list, so you can file with confidence.
Regulated by the professional bodies. Reviewed by qualified accountants. Part of Accotax.
Questions, answered.
The balancing payment is due by 31 January after the tax year ends. Payments on account may also be due on 31 January and 31 July.
Enter your profit after allowable expenses. Claiming every allowable expense lowers the tax.
Next steps
Keep exploring
Know your price before we start.
- Fixed fee confirmed in writing before any work begins
- ICAEW, ACCA and AAT-qualified accountants
- Filed with HMRC and confirmed, so you have proof
- A real person on the phone: 0203 4411 258