Answers · UK 2025/26
What is the deadline if I want to file a paper Self Assessment return instead of online?
31 October following the end of the tax year - three months earlier than the online deadline. For the 2025/26 tax year, paper returns are due by midnight 31 October 2026, while online returns have until 31 January 2027. Miss the paper date and you face the GBP 100 late-filing penalty even if you later file online on time.
Full answer
Self Assessment has two filing deadlines. Online returns are due by 31 January after the tax year ends. Paper returns must reach HMRC three months earlier, by 31 October. Worked example: Tom wants to file his 2025/26 return on paper. The tax year ended 5 April 2026, so his paper deadline is 31 October 2026. If he posts it on 15 November 2026, he gets an automatic GBP 100 late-filing penalty, even though the online deadline of 31 January 2027 has not yet passed. To avoid the penalty he would need to switch to filing online before 31 January 2027 instead. The payment deadline does not change: any tax owed for 2025/26 is still due by 31 January 2027 regardless of how you filed, and a 5% late-payment penalty applies to amounts still unpaid 30 days after that. Most people now file online because it is faster, the tax is calculated automatically, and you get the later deadline. Paper filing suits those who cannot use the online service or have circumstances HMRC's software does not handle. If you have missed the paper deadline, file online instead. Use the income tax calculator to estimate what you will owe so you can budget for the 31 January payment date. Confirm deadlines and request a paper form at gov.uk/self-assessment-tax-returns/deadlines.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.