Donaldson R F UK Tax Year Dates & Self Assessment Deadlines
See when any UK tax year runs, and the Self Assessment filing and payment deadlines that go with it.
These are the standard annual deadlines. HMRC can set a different deadline in individual cases, for example if you were sent a notice to file late. Source: GOV.UK: Self Assessment tax returns, deadlines (checked 7 October 2026).
How the UK tax year works
The UK tax year always runs from 6 April to 5 April the following year. If you're filing Self Assessment for that year, a paper return is due by 31 October after the tax year ends, and an online return and any tax owed (the "balancing payment") are due by 31 January the year after that. If you make payments on account towards next year's bill, the first is due on that same 31 January, and the second on 31 July that year.
Source: GOV.UK: Self Assessment tax returns, deadlines. Checked 7 October 2026.