GOV.UK
Self Assessment tax returns
4. 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 2016 and ended on 5 April 2017.
| Self Assessment | Deadline |
|---|---|
| Register for Self Assessment if you’re self-employed or a sole trader, not self-employed, or registering a partner or partnership | 5 October 2017 |
| Paper tax returns | Midnight 31 October 2017 |
| Online tax returns | Midnight 31 January 2018 |
| Pay the tax you owe | Midnight 31 January 2018 |
There’s an additional 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.
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. You must be eligible.
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 can’t send a return online.
HMRC might also email or write to you giving you a different 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
2015 to 2016 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.