Estimate your UK self-assessment tax bill for 2025/26, income tax, Class 2 and Class 4 NIC for sole traders, plus dividend tax for directors.
An informational calculator from COPA Accounting. We don't currently offer self-assessment as a stand-alone service.
Set aside enough for Income Tax and any Class 4 National Insurance on your profits, allowing for your other income and tax already paid. Keep extra cash for payments on account where they apply, because these advance payments are not included in this estimate.
Being a company director alone does not mean you need a Self Assessment return, and dividends above the £500 allowance may require telling HMRC rather than automatically filing one. Use HMRC’s check tool to confirm your circumstances, and file if HMRC has issued a notice to submit a return unless it withdraws that notice.
For 2026/27, the online return and balancing payment are normally due by 31 January 2028. Payments on account, where required, are normally due on 31 January and 31 July, so budget for these as well as the balance.
Employment income and sole trader profits share your Personal Allowance and non-savings Income Tax bands, so a side business can push income into a higher band. Sole trader profits can also attract Class 4 National Insurance; this estimate uses England, Wales and Northern Ireland Income Tax bands and excludes employee NI already handled through payroll.
The dividend allowance is £500 in 2026/27, with dividend tax rates of 10.75%, 35.75% and 39.35% above available allowances. Your salary and other income affect which dividend bands apply, so do not budget using the basic dividend rate alone.
HMRC may ask for a balancing payment plus the first payment on account towards the following year on the same January deadline. Payments on account normally apply unless the relevant bill is below £1,000 or more than 80% of your tax was collected at source.