How to use it
Find your jurisdiction, then follow the link to the tax authority’s own page. The authority governs — this table is a signpost, not a source of truth.
What it does not cover
Extensions, agent-filing deadlines, instalment obligations, state or cantonal variation, and the many situations in which an individual’s deadline differs from the ordinary one. It also does not tell you what you owe, only when the ordinary filing date falls.
Questions
Is this tax advice? No. It is a summary of published filing dates. Your position depends on your circumstances and residence.
How often is it reviewed? Quarterly, and the review date is shown on the page.