Self-employed2 min read · Updated 19 October 2026
Self-employed tax in the UK: what to set aside and when you pay
Income tax, Class 4 National Insurance, payments on account and the dates, with a worked example for a sole trader.
A worked example
| Turnover | £50,000 |
| Expenses | £10,000 |
| Profit | £40,000 |
| Income tax | £5,486 |
| Class 4 National Insurance | £1,646 |
| Set aside | £7,132 |
| Left for you | £32,868 |
Dates to know
Register for Self Assessment by 5 October after the tax year. File online and pay by 31 January. Payments on account are due 31 January and 31 July, with any balance due the next 31 January.
The trading allowance
If your self-employed income is small, you can use the £1,000 trading allowance instead of deducting expenses. Use whichever gives the lower profit.
A simple habit
Move the set-aside percentage into a separate savings account each time you are paid. Interest on it may count toward your savings allowance.
Common questions
How much tax do I pay on self-employed income?
Income tax at the normal rates after your Personal Allowance, plus Class 4 National Insurance on profit. On £40,000 that is about £7,132.
What are payments on account?
Advance payments toward next year, each half of your last bill, due 31 January and 31 July.
Do I pay Class 2?
It is no longer compulsory, and your State Pension credit is protected above the profit limit.