Use the calculator
Uses Income Tax rates for England, Wales and Northern Ireland.
How this calculator works
If you are a sole trader or a partner in a partnership, you pay Income Tax and National Insurance on your profit: your business income minus allowable expenses. Enter your taxable profit for the year and the calculator works out:
- Personal Allowance: £12,570, reduced by £1 for every £2 of income above £100,000.
- Income Tax: 20% on the first £37,700 of taxable profit, 40% up to £125,140 and 45% above.
- Class 4 National Insurance: 6% on profits between £12,570 and £50,270, and 2% on profits above £50,270.
- Class 2 National Insurance: if your profits are £7,105 or more, you do not pay Class 2 but are treated as having paid it, which protects your State Pension record. Below £7,105 you can choose to pay voluntarily at £3.65 a week. Use the setting to add this (£189.80 for 52 weeks).
The calculator assumes your profit is your only income. If you also have a job, a pension or rental income, your tax will be different because the Personal Allowance and tax bands are shared across all your income.
Worked examples
These figures come from running this calculator and were checked by hand against the GOV.UK rates.
Example 1: £30,000 profit
Taxable profit after the Personal Allowance is £17,430. Income Tax at 20% is £3,486 and Class 4 at 6% is £1,045.80. Total: £4,531.80, leaving £25,468.20 (an effective rate of 15.11%).
Example 2: £60,000 profit
Income Tax is £7,540 on the basic-rate band plus 40% of £9,730 (£3,892), a total of £11,432. Class 4 is 6% of £37,700 (£2,262) plus 2% of £9,730 (£194.60), which is £2,456.60. Total: £13,888.60, leaving £46,111.40.
Example 3: £6,000 profit with voluntary Class 2
No Income Tax or Class 4 is due. Paying Class 2 voluntarily costs £189.80 for the year and can count towards your State Pension.
2026/27 rates for the self-employed
| Item | Rate or threshold |
|---|---|
| Personal Allowance | £12,570 |
| Basic rate Income Tax | 20% on the first £37,700 of taxable profit |
| Higher rate | 40% up to £125,140 |
| Additional rate | 45% above £125,140 |
| Class 4 main rate | 6% on profits from £12,570 to £50,270 |
| Class 4 upper rate | 2% on profits above £50,270 |
| Class 2 | Treated as paid with profits of £7,105 or more; voluntary £3.65 a week below that |
Assumptions and what this calculator does not cover
- Other income: employment, pension, savings, dividend and rental income are not included.
- Working out profit: you need to deduct allowable expenses, or use the £1,000 trading allowance instead, before entering a figure. The calculator does not do this.
- Scotland: Scottish taxpayers pay Scottish Income Tax on profits; Class 4 is the same across the UK.
- Student loans and pensions: student loan repayments collected through Self Assessment and pension contributions are not included.
- Losses, allowances and reliefs: capital allowances, losses, the Marriage Allowance and other reliefs are not modelled.
When you pay: Self Assessment and payments on account
Self-employed tax is paid through Self Assessment. The deadline for online returns and for paying any balance is 31 January after the end of the tax year. If your last tax bill was more than £1,000, HMRC will usually ask for payments on account: two advance payments towards next year’s bill, due on 31 January and 31 July, each normally half of the previous year’s bill. This applies unless more than 80% of your tax was already deducted at source. In your first year of trading, that can mean paying the balance for one year plus the first payment on account for the next on the same day, so setting money aside each month helps.
A common approach is to move a fixed share of every payment you receive into a separate savings account. Use the effective rate from the calculator as a starting point. The budget planner can help you plan the rest of your income, and the disposable income guide explains what is left after essentials.
Frequently asked questions
Do I still pay Class 2 National Insurance?
Not if your profits are £7,105 or more: you are treated as having paid it, so your State Pension record is protected at no cost. Below £7,105 you can pay voluntarily at £3.65 a week.
What is the Class 4 rate for 2026/27?
6% on profits between £12,570 and £50,270, and 2% above £50,270.
Is the tax on profit or turnover?
On profit: your income minus allowable business expenses.
What are payments on account?
Advance payments towards your next tax bill, usually due on 31 January and 31 July, if your last bill was more than £1,000.
Sources
- GOV.UK: Self-employed National Insurance rates
- GOV.UK: Income Tax rates and Personal Allowances
- GOV.UK: Self Assessment tax returns
- GOV.UK: Payments on account
Rates for tax year 2026/27, last reviewed October 2026.
Results are estimates for planning, not financial or tax advice. See our terms and methodology.