Self Assessment tax returns
Deadlines
HM Revenue and Customs (HMRC) must receive your tax return and any money you owe by the deadline.
The last tax year started on 6 April 2022 and ended on 5 April 2023.
Deadline for telling HMRC you need to complete a return
You must tell HMRC by 5 October if you need to complete a tax return and have not sent one before.
You can tell HMRC by registering for Self Assessment.
Deadline for submitting a paper return
If you’re doing a paper tax return, you must submit it by midnight 31 October 2023.
Deadline for submitting an online return
If you’re doing an online tax return, you must submit it by midnight 31 January 2024.
Deadlines for paying tax you owe
You need to pay the tax you owe by midnight 31 January 2024.
There’s usually a second payment deadline of 31 July if you make advance payments towards your bill (known as ‘payments on account’).
You’ll usually pay a penalty if you’re late. You can appeal against a penalty if you have a reasonable excuse.
If you do not know your profit for the whole tax year
You might not know what your profit will be for the whole tax year if, for example:
- your ‘accounting period’ ends at a different time to the end of the tax year
- your ‘accounting period’ is different to your ‘basis period’
- you’re waiting for a valuation
An ‘accounting period’ is the period which a business’s accounts are made up to (often 12 months) and gives the business year end. This can be different to the period used to identify the profits taxable in any particular tax year (also known as a ‘basis period’).
If you do not know what your profit will be for the whole tax year before the reporting deadline, you should work out what it’s likely to be (known as ‘provisional figures’) and include those.
You should tell HMRC that you’ve used provisional figures when you submit your return.
When you find out what your profit was for the whole tax year, you’ll need to change your return. You have 12 months from the Self Assessment deadline to make these changes.
If more tax is due, you’ll need to pay interest on the difference between your estimates and the final figures. The interest will be worked out from the original due date for payment. If you have overpaid tax then you’ll get interest paid to you.
When the deadline is different
Submit your online return by 30 December if you want HMRC to automatically collect tax you owe from your wages and pension. Find out if you are eligible to pay this way.
HMRC must receive a paper tax return by 31 January if you’re a trustee of a registered pension scheme or a non-resident company. You cannot send a return online.
HMRC might also email or write to you giving you a different deadline if they were late in sending out your return.
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
2021 to 2022 tax year and earlier
The Self Assessment deadline for these tax years has passed. Send your tax return or payment as soon as possible - you’ll have to pay a penalty.