Deadlines and admin
Self Assessment deadlines for 2025/26 and 2026/27
Two tax years are in play at once: the one you are filing for and the one you are trading in now.
The 2025/26 return, for the year that ended on 5 April 2026, must reach HMRC online by 11:59pm on 31 January 2027, and the tax for that year is due the same night; the 2026/27 return follows a year later, on 31 January 2028. Around that central date sit four others. Newcomers must register by 5 October 2026. Paper returns are due earlier, by 31 October 2026. Anyone who wants a balance paid through their tax code has to file online by 30 December 2026. And sole traders who make payments on account pay the second one on 31 July 2027. Sole traders already in Making Tax Digital keep the January dates and add quarterly updates. Choose a tax year below to see its full set of dates.
Self Assessment dates for a tax year
Online return and payment
31 January 2027
| Tax year ends | 5 April 2026 |
| Register if new | 5 October 2026 |
| Paper return | 31 October 2026 |
| Online, to pay through your tax code | 30 December 2026 |
| Second payment on account | 31 July 2027 |
Figures checked by Radif Partners · Editorial policy · How we calculate
The full calendar, year by year
| Tax year | Register if new | Paper return | Online, for coding out | Online return and payment | Second payment on account |
|---|---|---|---|---|---|
| 2025/26 | 5 October 2026 | 31 October 2026 | 30 December 2026 | 31 January 2027 | 31 July 2027 |
| 2026/27 | 5 October 2027 | 31 October 2027 | 30 December 2027 | 31 January 2028 | 31 July 2028 |
| 2027/28 | 5 October 2028 | 31 October 2028 | 30 December 2028 | 31 January 2029 | 31 July 2029 |
Read across a row and the pattern is always the same: the tax year closes on 5 April, registration is due six months later, the paper return three and a half weeks after that, and the online return with the money at the end of the following January. The only date that belongs to a different year is 31 July, which is a payment towards the year after.
What each date means for a sole trader
5 October: telling HMRC
This one concerns you only in your first year, or if you return to Self Assessment after a year without a return. Miss it and HMRC gives you three months from its letter to file, but the January payment date does not move. The registration guide covers who has to register.
31 October: paper returns
A paper return has to be in HMRC’s hands, not just in the post, by 31 October 2026 for 2025/26. A paper return sent later is late even though an online one would not be.
30 December: coding out
HMRC can collect a Self Assessment balance through your tax code in the following year instead of asking for a lump sum, which only works if you also have wages or a pension taxed under PAYE. The condition is filing online by 30 December 2026. Miss it and you pay the usual way in January.
31 January: the return and the bill
Two obligations share this date. The online return must be submitted, and everything owed for the year must be paid: the balancing payment, plus the first payment on account for the current year if you make them. Take a picture framer with £32,000 of profit in 2026/27 and no payments on account yet: on 31 January 2028 the framer pays £5,052 for the year and £2,526 towards the next one (GOV.UK, Self Assessment deadlines).
31 July: the second instalment
Payments on account are due on 31 January and 31 July. The July payment is the second half of the advance towards the current year’s bill, worked out from last year’s figure. It does not exist for anyone whose last bill was under £1,000. The payments on account calculator shows how the two halves are set.
GOV.UK lists a payment plan as the option for anyone who does not think they can pay on time. Filing early gives you the figure months ahead, and so leaves room to set one up.
When figures are not ready
A business whose accounts end on a date other than 5 April, or which is waiting for a valuation, may not know its final profit by 31 January. GOV.UK says to file anyway with provisional figures, tell HMRC that you have done so, and amend the return when the real numbers arrive. Amendments can be made for twelve months after the filing deadline. If more tax turns out to be due, interest runs from the original payment date.
What Making Tax Digital adds
Sole traders whose qualifying income brought them into Making Tax Digital from 6 April 2026 keep the January dates for the return and the payment, and add four quarterly updates. These are due on 7 August, 7 November, 7 February, 7 May. For 2026/27 no penalty point is given for a late quarterly update, though the updates still have to be sent before the return can be filed (HMRC, MTD penalties). Penalties change too, from the first year you are in the scheme; the quarterly deadlines page sets out the update periods, and the penalties page explains which regime applies to which return.