Self Assessment & Personal Tax
Self Assessment 2025/26 — deadlines, who files, penalties
Pillar guide to UK Self Assessment for 2025/26 — due 31 January 2027.
Self Assessment is how HMRC collects Income Tax from people whose tax is not fully taken at source — the self-employed, company directors with untaxed income, landlords, and higher earners. For 2025/26 (which ended 5 April 2026): register by **5 October 2026** if new, file paper by **31 October 2026**, or file online and pay any tax owed by **31 January 2027**. Missing the online deadline triggers an automatic **£100** penalty even if you owe nothing. From 6 April 2026, self-employed people and landlords with qualifying income over £50,000 move to Making Tax Digital and stop filing the traditional annual return. **Read the full pillar at [rraccountants.uk/self-assessment](https://rraccountants.uk/self-assessment).**
Resources
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