For the tax year ending 5 April 2018, the deadlines for self-assessment tax returns are:

• 31 October 2018 – paper.
• 30 December 2018 – online if you owe less than £3,000 and want it collected through next year's tax code.
• 31 January 2019 – online.

If you miss the deadline you'll be subject to the late filing penalty rules.

There are two exceptions when the paper deadline is extended to 31 January 2019:

• Certain people are excepted from the 31 October 2018 paper deadline – if this applies to you, HMRC will notify you.
• HMRC's online systems can't accept certain items or combinations of information and this might mean that you can't file online. Where possible the TaxCalc program will advise you of this, but if you're in any doubt, TaxCalc Support will be able to help.

The following table shows the deadlines for previous years.