Self Assessment Tax Calculator
Estimate your Self Assessment bill as a sole trader — Income Tax, Class 4 National Insurance and your payments on account.
More options — other income, savings & dividends, reliefs, student loan, child benefit, tax year
How to use it
- Enter your profit. Use your trading profit (income minus allowable expenses).
- See your bill. PayGlance estimates Income Tax and Class 4 NIC for 2026/27.
- Plan your payments. It also shows the payments on account HMRC will ask for.
FAQs
What does this include?
Income Tax and Class 4 National Insurance on a sole trader's trading profit, plus your payments on account. It excludes other income and reliefs.
What are payments on account?
Advance payments toward next year's bill — usually two instalments, each half of this year's tax, due in January and July.
When is it due?
The online Self Assessment deadline is 31 January after the tax year ends.