Self Assessment tax returns
Deadlines
HM Revenue and Customs (HMRC) must receive your tax return and any money you owe by the deadline.
If you do not know your profit for the whole tax year, you still need to send a tax return. Check how to send a return if you do not know your profit for the whole year.
The last tax year started on 6 April 2024 and ended on 5 April 2025. The deadline for earlier tax returns has passed and you may have to pay a penalty. Send your tax return or payment as soon as possible to avoid further penalties.
Telling HMRC you need to complete a return
You must register for Self Assessment by 5 October 2025 if you need to complete a tax return and have not already registered.
If you register after 5 October 2025
HMRC will send you a letter or email with a different deadline to send your tax return by - this will be 3 months from the date on the letter or email.
You must still pay the tax you owe by 11:59pm on 31 January 2026 or you’ll get a penalty.
Sending a paper tax return
HMRC must receive your paper tax return by 11:59pm on 31 October 2025 or you’ll get a late filing penalty.
You can send it any time on or after 6 April 2025 as long as HMRC receives it by the deadline.
Submitting an online tax return
You must submit your online tax return by 11:59pm on 31 January 2026 or you’ll get a late filing penalty.
If you want to pay your Self Assessment bill through your tax code, you must submit it by 11:59pm on 30 December 2025. If you miss this deadline, you’ll have to pay another way.
You can submit your return any time on or after 6 April 2025 up to the deadline.
Paying the tax you owe
You need to pay your Self Assessment tax by 11:59pm on 31 January 2026 or you’ll get a penalty.
There is a second payment deadline of 31 July if you make payments towards your bill - these are known as ‘payments on account’.
You can estimate your Self Assessment tax bill before sending your tax return to:
- give you an idea of what your bill is likely to be
- allow you to budget and pay on time
Find help on understanding the tax you owe.
Trustees of a registered pension scheme or non-resident companies
HMRC must receive a paper tax return by 31 January 2026. You cannot send a return online.
You can send it any time on or after 6 April 2025 as long as HMRC receives it by the deadline.
Partnership returns if you have a company as a partner
If your partnership’s accounting date is between 1 February and 5 April and one of your partners is a limited company, the deadline for:
- online returns is 12 months from the accounting date
- paper returns is 9 months from the accounting date