Paper Self Assessment deadline falls on 31 October as HMRC urges early filing

People sending a paper Self Assessment return for the 2025–26 tax year face the standard deadline of 31 October 2026, with HM Revenue & Customs required to receive it by 11:59pm that day. The online filing deadline is later: 11:59pm on 31 January 2027, when tax owed is also normally due.

HMRC renewed its call for early filing on 23 October, saying around 12 million people are expected to submit a return. It said completing the process sooner gives taxpayers more time to understand their bill and plan how to pay it.

The dates apply to different tasks

The paper deadline is a receipt deadline. Posting a form on 31 October is therefore not the same as ensuring it reaches HMRC on time. The tax year covered ran from 6 April 2025 to 5 April 2026.

New filers should check their registration position

People entering Self Assessment for the first time need to register and obtain a Unique Taxpayer Reference before completing their return. HMRC directs anyone unsure whether a return is needed to its GOV.UK checking service.

The official guidance sets out a separate filing timetable for people who register after 5 October 2026: HMRC sends a letter or email giving a deadline three months from its date. The tax payment deadline remains 31 January 2027. Other special rules apply to registered pension scheme trustees, non-resident companies and some partnerships, so those filers should check the relevant section of the guidance.

HMRC also says customers signed up to Making Tax Digital for Income Tax still need to send their 2025–26 Self Assessment return in the usual way and pay what they owe by 31 January.

Support is available through GOV.UK

The department lists help with individual sections of the return, explanatory videos and a digital assistant among its support options. Taxpayers can also seek help from a tax agent or a voluntary organisation.

Its reminder warns that criminals impersonate HMRC to obtain money or personal information. HMRC advises people to check unexpected requests, avoid links in unexpected messages and keep their sign-in details private.