Updated on 6 April 2026

Tax return deadlines

To avoid being charged a late filing penalty, make sure you understand when your Self Assessment tax return should be filed.

a calendar with a sticky note attached, note says in back ink 'FILE TAX RETURN!'
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Due dates

The due date for a Self Assessment tax return depends on:

  • the date of issue of the notice that HMRC send you to tell you to complete a tax return, and 
  • whether you complete your tax return on paper or online. 

If you are filing your Self Assessment tax return on paper, you should also bear in mind the date by which you must send in your tax return if you want HMRC to calculate your tax liability for you. 

The table below summarises the position for Self Assessment tax returns for 2025/26 (the tax year which ended on 5 April 2026):

Date notice to file issued by HMRC Deadline for submitting paper return Deadline for submitting return to HMRC to
calculate tax (paper returns only)		 Deadline for submitting return online
On or before 31 July 2026 31 October 2026 31 October 2026 31 January 2027
1 August 2026 to 31 August 2026 3 months from date of notice 31 October 2026 31 January 2027
1 September 2026 to 31 October 2026 3 months from date of notice 2 months from date of notice 31 January 2027
After 31 October 2026 3 months from date of notice 2 months from date of notice 3 months from date of notice
HMRC notice to file a self assessment tax return for the tax year ending on 5 April, issued on 30 April. Taxpayer has to file the tax return by 31 October if on paper or 31 January if online.
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Example – paper tax return 

Alfie notified HMRC that he would need to complete a 2025/26 tax return on 17 September 2026. He doesn’t have a computer, so he requested a paper tax return. HMRC sent a paper return to him to complete. The date of issue of the paper tax return was 1 October 2026. 

If he wants HMRC to calculate his tax liability for him, Alfie needs to send the form in time for it to reach HMRC by 1 December 2026, that is, within two months of the date of issue of the return.

But if Alfie is happy to calculate his tax bill himself then he will have a deadline of three months from 1 October 2026 for HMRC to receive his paper tax return – so by 1 January 2027.

Example – online tax return

Pablo is sent a notice to file a Self Assessment tax return for the 2025/26 tax year which is dated 10 April 2026. Therefore, he must file the return online by 31 January 2027. But if he decides to file a paper tax return, he must make sure that HMRC receive it by 31 October 2026.

  We suggest that you keep evidence of your tax return submission in case HMRC require confirmation that the return was submitted and the date of submission. If possible, when sending a paper tax return to HMRC, use a tracked delivery service and keep your proof of sending.  If you submit your tax return online you will receive an email from HMRC confirming your submission. 

PAYE code adjustment for tax owed

If you owe less than £3,000 for the year and want HMRC to collect this by adjusting your PAYE code, you must submit a paper return by 31 October or an online return by 30 December following the end of the tax year. For 2025/26, this means that HMRC must receive your paper return by 31 October 2026, or you must submit your online return by 30 December 2026 for the tax to be collected via your 2027/28 PAYE code. Note that the online deadline date is 30 December, not 31 December.

We explain more about paying Self Assessment tax via your PAYE code on our Self Assessment tax payments page.

Penalties for late filing

If you do not submit your Self Assessment tax return by the due date, then (unless you have volunteered for the new penalty system to apply to you) you will automatically be charged a late filing penalty of £100. HMRC continue to charge penalties the longer you delay. See Tax penalties and interest for more details.

HMRC take the date of the first return received by them for the purposes of calculating late filing penalties. For example, if you file a paper return for 2025/26 after 31 October 2026, you cannot avoid a late filing penalty by filing the return again online before 31 January 2027. However, if you intended to file on paper but miss the 31 October deadline, then you can avoid a penalty by filing the return online instead as long as you do so by the following 31 January.

Partnerships

If you are a partner in a partnership, note that HMRC do not provide an online partnership return. Therefore, if you want to file online you will need to file the partnership return by other means (such as via a tax adviser or using third party software). Otherwise, you must file a paper version of the return by the relevant paper due date to avoid late filing penalties in relation to the partnership tax return. 

  If the partnership return is filed after the relevant due date, each partner who was registered in the partnership during that tax year will receive a late filing penalty from HMRC.

For more information on late filing penalties for partnerships, see HMRC’s manual.

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