Self Assessment deadlines for sole traders
Pick a tax year and see every date that matters, counted from today. It lists the dates only: it does not work out what you owe.
Self Assessment deadlines for sole traders
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Registering comes first
If you have never filed a return, you tell HMRC by registering for Self Assessment by 5 October after the tax year ends. Miss it and HMRC will send you a letter with a deadline, but the 31 January payment date does not move.
Online is later than paper
A paper return has to reach HMRC by 31 October. Online is 31 January. File online by 30 December if you want what you owe collected through your tax code.
Paying is a separate date
Filing and paying are not the same job. Tax owed is due by 31 January, and a second payment on account falls on 31 July. Late filing or late payment can lead to penalties.
Figures for the 2026/27 tax year, checked 25 October 2026. Sources: Self Assessment tax returns deadlines. An estimate, not advice. SideTill is not tax software.
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Questions
Is 31 January the deadline for everything?
For an online return and for paying what you owe, yes. Paper returns, registering and collecting through your tax code all have earlier dates.
What is a payment on account?
An advance payment towards next year's bill, made in two halves. The second is due 31 July. The first falls on 31 January, alongside the bill for the year just filed.
Does this work out what I owe?
No. It is the calendar only. Get your number from your return, or try the take-home estimate on this site for a rough idea.