Tax Deadlines
PayToolkit's tax deadlines articles: practical UK tax guidance, worked examples, and links to the right free calculator for each topic.
Missing an HMRC deadline is one of the most avoidable ways to lose money — a late Self Assessment return triggers an automatic £100 penalty even if you owe nothing, and it escalates from there. This section covers the dates that matter for the 2026/27 tax year: the 31 January online filing and balancing payment deadline, the 31 July second Payment on Account deadline, and the 5 October deadline to register if you're newly self-employed.
We also explain Payments on Account in plain English — why HMRC asks you to pay next year's tax in advance, and how to apply to reduce them if your income has dropped. For a live, personalised view of what's due and when, use the free Tax Dashboard, or see the full list of dates on our Self Assessment deadlines page.
Payments on Account Explained: Why HMRC Wants Tax in Advance
Understand how advance tax payments work, who needs to make them, and how to reduce them if your income has dropped.
Self AssessmentSelf Assessment Checklist 2026/27: Documents, Deadlines & Steps
Everything you need to gather before filing your tax return. All documents, deadlines, and step-by-step filing guidance for 2026/27.
Self AssessmentHow to Calculate Your Self Assessment Tax Bill 2026/27
Step-by-step guide to working out your Income Tax, Class 2 and Class 4 NICs, payments on account and key deadlines for 2026/27.