Missed the January filing deadline? Here’s what to expect

04 February 2026 | Mrge_Acontants

Thousands of people once again took the chance to use some quiet time over the festive period to file their self-assessment tax returns, with 4,606 people even filing their return on Christmas Day.

In total, 37,435 people completed their return over the three days of festivities, Christmas Eve, Christmas Day and Boxing Day. But there are still thousands more taxpayers who are yet to file, which means they could be facing penalties for late filing after the January 31 deadline.

The penalties start as soon as you miss the deadline, whether there was any tax to pay to HMRC or not. If you are only due to file a self-assessment return to deal with the High Income Child Benefit Charge, there is a new PAYE digital service. If you had signed up to this before January 31, you could opt out of filing a self-assessment and chosen to pay back any money you owed through your tax code. But if you have missed the deadline, then for now, you still need to file a self-assessment.

How do the penalties work?

If you have to file a self-assessment tax return, you must file before January 31, 2026. If you missed this deadline, or you failed to pay your bill on time, then you will face a penalty.

You will immediately face a £100 penalty for filing late. If you still haven’t filed your return within three months, you will face additional daily penalties of £10 per day, to a maximum of £900. If you haven’t filed after six months, you will face a further penalty of 5% of the tax due, or £300, whichever is higher. If you haven’t filed within 12 months, then another 5% of the tax due is added, or an additional £300, whichever is greater.

If you’re filing your return as part of a partnership and it is filed late, then every partner will be charged a penalty. These are 5% of the tax due at 30 days, six months, and 12 months, plus interest on the amount owed.

What else do I need to know?

If you register for self-assessment after October 5, and also don’t file your return and pay your tax bill on time, you may get a ‘failure to notify’ penalty, according to HMRC. You can find more information on ‘failure to notify’ penalties on Gov.uk.

If you get a penalty, then you need to pay it within 30 days of the date on the penalty notice. You can appeal against a penalty if you disagree with it. However, if there is a good reason why you couldn’t file your self-assessment or pay your tax bill, such as being in hospital or losing a close relative, then you may be able to get the penalty waived.

If you find yourself in a situation where you are facing a tax penalty for any reason, then the best thing to do is speak to your accountant as soon as possible, and give as much information as you can to resolve the issue quickly.

We can help you meet your obligations

If you receive a penalty notice, or know you haven’t met your tax and filing obligations in good time, then please get in touch and we would be happy to give you the guidance you need.