What if you miss the Self Assessment tax return filing deadline?

Running your own small business can be very demanding and at times it can seem like there just aren’t enough hours in the day. And when there are so many things to do and various deadlines…

5 Minute Read

Last Updated: 23rd March 2023

Running your own small business can be very demanding and at times it can seem like there just aren’t enough hours in the day. And when there are so many things to do and various deadlines to meet, it’s hardly surprising that some get missed – including filing your Self Assessment tax returns before the deadline.

The self-employed (aka sole traders) make up 59% of the UK’s 6m strong business population, so it’s hardly surprising that Self Assessment tax returns (ie SA100s) are most likely to be filed late.

What does HMRC consider to be “late”?

No ifs or buts, late is any time after the required filing deadline. So, the deadline for online filing of your Self Assessment tax return is midnight on 31 January (eg 31 January 2022 for the 2020-21 tax year). Even if you file your return one second, minute, hour or day late, you’ll have missed the filing deadline and will face having to pay a late-filing penalty.

Late filing penalties for missing Self Assessment deadlines

Self-employed people and others who must complete a Self Assessment tax return but miss the filing deadline may have to pay:

  • The fixed Self Assessment late filing penalty of £100, payable to HMRC as soon as you miss the deadline.
  • After three months, if you still fail to submit your Self Assessment tax return, you’ll face an additional £10 daily penalty, up to a £900 maximum.
  • If you’re six months late, you can expect a further penalty of £300 or 5% of the tax owing if this is greater.
  • Those who are 12 months late are charged another £300 or 5% of the tax owing if this is greater.

Obviously, the more tax you owe and the later you file, the higher the penalty. Government website GOV.UK features an online tool that enables you to estimate your penalty for late Self Assessment tax returns and payments. If you’re part of an ordinary partnership and your Self Assessment tax return is filed late, you and your fellow partner(s) may have to pay a late filing penalty.

Need to know! You can pay a penalty if your Self Assessment tax return contains mistakes that HMRC believes are the result of you not taking reasonable during completion. Expect far higher penalties if incorrect information has been entered deliberately.

Appealing a late filing penalty

If you have a reasonable excuse, you can appeal against a Self Assessment late filing penalty. Reasonable excuses include:

  • Death of a partner or close relative shortly before deadline.
  • Serious, life-threatening illness or unforeseen hospital stay that prevented you from completing your tax return.
  • Delays caused by disability.
  • Serious computer or software failure shortly before or while preparing/filing your return online.
  • Serious issues with HMRC’s online services.

More recently, HMRC has accepted coronavirus as a reasonable excuse for late filing, but in all cases, returns must be filed as soon as possible (within 14 days preferably). Also, you should file your tax return before appealing your late filing penalty. Initially, you appeal to HMRC, within 30 days of the penalty notice being issued, but HMRC may consider late appeals in some circumstances.

Claiming that someone else failed to file your return on time isn’t an acceptable excuse, nor is finding it hard to use HMRC’s online system or not knowing when the deadline was. In other cases, visit Gov.uk to find out how to appeal a Self Assessment penalty.

How to prevent late filing problems

If you plan doing your Self Assessment tax return into your annual diary, set up automatic reminders and leave yourself enough time for completing and filing, you’re much less likely to miss deadlines. Investing in the right software can save you lots of time and hassle, making it much easier to complete your tax returns accurately, quickly and efficiently.

Filing your tax returns online gives you more time (HMRC’s deadline for paper Self Assessment tax returns is midnight 31 October, three months before the online filing deadline). If you dislike financial record keeping and tax returns really aren’t your thing, budget permitting, you could get help from an experienced service provider. Not only could it make your life less stressful when tax-return filing dates approach, but it could also free you up to do things that contribute far more value to your business.

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Blog content is for information purposes and over time may become outdated, although we do strive to keep it current. It's written to help you understand your Tax's and is not to be relied upon as professional accounting, tax and legal advice due to differences in everyone's circumstances. For additional help please contact our support team or HMRC.

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