Use this self employed tax calculator to estimate the Income Tax and Class 4 National Insurance on your sole trader profits, and how much to set aside each month. Enter your turnover and expenses, or use the £1,000 trading allowance, and add any salary you also earn.
Your self-employed tax bill
- Taxable profit
- –
- Income Tax
- –
- Class 4 NI
- –
- Total tax and NI
- –
- You keep
- –
| Year | Month |
|---|
In the example, £50,000 of turnover with £8,000 of expenses gives a profit of £42,000. The tax bill is £5,886.00 Income Tax plus £1,765.80 Class 4 National Insurance, a total of £7,651.80, or about £638 a month to put aside.
How to use the self employed tax calculator
- Enter your turnover: all the money your business took in during the tax year (6 April to 5 April).
- Enter your allowable expenses, or tick the box to use the £1,000 trading allowance instead. You cannot use both.
- Add any other income, such as a salary from a job. Tax on it is normally paid through PAYE, but it pushes your profit into higher bands.
- Choose where you live. Scotland has its own Income Tax bands. National Insurance is the same across the UK.
What tax do self-employed people pay?
As a sole trader you pay tax on your profit, not your turnover. Profit is the money coming in less allowable business expenses. Two taxes apply:
- Income Tax at the same rates as employees. In England, Wales and Northern Ireland that is 20% from £12,571, 40% from £50,271 and 45% above £125,140.
- Class 4 National Insurance at 6% on profits between £12,570 and £50,270, and 2% above that. See the GOV.UK National Insurance rates for self-employed people.
Class 2 National Insurance is no longer charged. If your profits are below the small profits threshold of £7,105, you can pay voluntary Class 2 contributions to protect your State Pension record.
Self employed tax examples
This table shows what the self employed tax calculator gives for different profits, with no other income, in England, Wales or Northern Ireland:
| Profit | Income Tax | Class 4 NI | Total | Share of profit |
|---|---|---|---|---|
| £15,000 | £486 | £146 | £632 | 4.2% |
| £20,000 | £1,486 | £446 | £1,932 | 9.7% |
| £30,000 | £3,486 | £1,046 | £4,532 | 15.1% |
| £40,000 | £5,486 | £1,646 | £7,132 | 17.8% |
| £50,000 | £7,486 | £2,246 | £9,732 | 19.5% |
| £60,000 | £11,432 | £2,457 | £13,889 | 23.1% |
| £80,000 | £19,432 | £2,857 | £22,289 | 27.9% |
The rate you pay rises with profit, because more of it falls into the 40% band. Use the self employed tax calculator with your own figures rather than a flat percentage, especially if your profit is close to £50,270 or £100,000.
Allowable expenses and the trading allowance
Allowable expenses are costs you have only because of the business. Common ones include stock and materials, business travel, phone and internet, office costs, insurance, accountancy fees and a share of household bills if you work from home.
If your expenses are small, the £1,000 trading allowance may be better. It lets you take £1,000 off your income without proving any costs. If your turnover is £1,000 or less, you do not need to tell HMRC at all. Tick the box in the calculator to compare.
Working and self-employed at the same time
If you also have a job, your salary uses up your tax-free Personal Allowance first, so all of your self-employed profit is taxed. For example, with a £35,000 salary and a £15,000 side profit, the self employed tax calculator shows £3,000.00 Income Tax and £145.80 Class 4 NI on the profit. Enter your salary in the “other income” box to see your own figure.
Self employed tax calculator vs a tax return
A full tax return can include rent, savings, dividends, pension contributions, student loan repayments and losses brought forward. This tool focuses on trading profit, which is the biggest part of the bill for most sole traders. Use it through the year to budget, then complete your return with exact figures once your accounts are finished.
When to pay your Self Assessment tax
You report your profit on a Self Assessment tax return. Register by 5 October after the end of the tax year in which you started. The online return and any tax are due by 31 January.
If your bill is over £1,000, HMRC usually asks for payments on account: two advance payments towards next year, each half of this year’s bill, due on 31 January and 31 July. The first January this applies, you pay the full bill plus the first advance payment, so about one and a half times your bill. The calculator shows this in its note.
Making Tax Digital for sole traders
From April 2026, sole traders and landlords with qualifying income over £50,000 must keep digital records and send quarterly updates to HMRC. The threshold drops to £30,000 from April 2027 and £20,000 from April 2028. Check when you need to sign up.
Related tax calculators
Thinking of becoming a limited company? Compare with the corporation tax calculator and the dividend tax calculator. Employees can use our take home pay calculator, and landlords the rental income tax calculator.
Frequently asked questions
How much tax do I pay on £20,000 self-employed?
With no other income, a £20,000 profit means £1,486.00 Income Tax and £445.80 Class 4 National Insurance in England, Wales or Northern Ireland, £1,931.80 in total.
How much should I save for tax when self-employed?
A simple rule is 20% to 30% of your profit if you are a basic rate taxpayer, and more if you are a higher rate taxpayer or must make payments on account. The self employed tax calculator gives a monthly figure you can move into a separate savings account.
Is this a self assessment tax calculator?
It estimates the tax on self-employed profit that you report through Self Assessment. It does not include other income types such as rent, savings interest or dividends, which have their own calculators.
Do I pay National Insurance if I earn under £12,570?
No Class 4 NI is due below £12,570 of profit. You can choose to pay voluntary Class 2 contributions if you want the year to count towards your State Pension.
About this calculator
This self employed tax calculator uses 2026/27 Income Tax bands and Class 4 National Insurance rates. Figures were checked against GOV.UK on 9 November 2026. It does not include student loan repayments, pension contributions or losses. Results are estimates: your tax return or an accountant will give the exact figure.