Missed the Self Assessment deadline? Here’s what you need to do

Missed the Self Assessment deadline? You’re not alone.

Filing a Self Assessment tax return can be a daunting prospect and many people miss the 31 January deadline.

According to HMRC, 1.1 million people missed the tax return deadline in 2024.

If you are don’t know whether you needed to complete a Self Assessment tax return, you can use HMRC’s Self Assessment tool or check out this list below – you’ll need to complete a tax return if you:

• or your partner received child benefit and either of you had an annual income of more than £50,000.
• received more than £2,500 in other untaxed income, for example, from tips or commission; money from renting out a property; income from savings, investments and dividends; foreign income.
• are a self-employed sole traders and earned more than £1,000.
• are a partner in a business partnership.
• are an employee claiming expenses in excess of £2,500.
• have an annual income over £100,000.

The Self Assessment deadline of 31 January is also for any tax you owe for the previous tax year (known as a balancing payment) and your first payment on account.

There is also the 31 July deadline for your second payment on account.

In this article, we cover what you need to do now if you missed the 31 January deadline to file your tax return an pay your tax bill.

Here’s what we cover:

What to do if you missed the 31 January deadline

If you missed the 31 January deadline, the most important things to do are to not panic and get to work on filing your tax return as soon as you can.

However, as it’s late, there will likely be various penalties to be pay.

Be aware of the penalties

• An initial £100 fixed penalty, which applies even if there is no tax to pay, or if the tax due is paid on time.
• After three months, additional daily penalties of £10 per day may be charged, up to a maximum of £900.
• After six months, a further penalty of 5% of the tax due or £300, whichever is greater.
• After 12 months, another 5% or £300 charge, whichever is greater.
• There are also additional penalties for paying late of 5% of the tax unpaid at 30 days, six months and 12 months. Interest will be charged on all late payments.

Get in touch with HMRC now

Team Umbrella, a risk assessment agency firm that works with accounting agencies, offers the following advice if you’ve missed the Self Assessment deadline:

“If you get on the phone to HMRC immediately [when you know you have missed the deadline], HMRC can be sympathetic and might agree to allow you to pay off the fine in instalments suitable to your salary or earnings.

“The £100 fine has been known to be waived if extenuating circumstances are present and provable; if this is your first time then they might factor this into their decision.

“These fines are usually only rescinded once you’ve filed your new assessment, so there’s an incentive to get cracking.

“The second word of advice we have is to formalise your approach to tax going forward.

“Using accounting software or hiring an independent accountant for your business can be a wise investment and will take some of the stress out of tax next year.”

More on HMRC waiving penalties

Mariah Tompkins is the director of Derby-based accountancy firm WKM Accountancy Services.

Here, she goes into more depth into reasons why HMRC may waive your penalties:

“If you find yourself unable to submit your tax return due to any of the following situations, inform HMRC straight away.

“They may waive the penalties because:

• A close relative or partner died shortly before the deadline.
• You had an unexpected stay in hospital that prevented the submission of your tax return.
• You had a serious or life-threatening illness.
• There were service issues with HMRC online.
• The delay was related to a disability.

“It is not guaranteed that HMRC will waive the penalties as it depends on individual circumstances. You may also need to provide proof for your appeal.

“It’s also important to note that you will still need to file your tax return as soon as possible or the penalties will not be cancelled.”

Read more about Self Assessment

• Free e-book: Get Self Assessment right each time
• How to file a Self Assessment tax return online: A step-by-step guide
• Tax deductions UK: Allowable expenses you can claim if you’re self-employed
• What is payment on account and how do I pay it?
• Tax return tips: 7 tips to get your Self Assessment tax return right
• 7 top tips for filing your Self Assessment tax return

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What you need to do now to submit your tax return

If you’ve started your Self Assessment tax return but haven’t got round to finishing and filing it, take the time to do it now.

If you’re further back in the process, here are the steps you need to consider and action:

• Register with HMRC as either self-employed, not self-employed or as a partner or partnership.
• Once you register, you’ll be sent a Unique Taxpayer Reference (UTR), which you will need when you file your return. You can do so by post or online – the latter allows you to save drafts, review returns and print tax calculations. At this late stage, opt for online – it will be faster.
• If completing your tax return online, you’ll need to register for online services first. HMRC will send you an activation code. Allow up to a week for this to arrive.
• You’ll need to input the UTR, activation code and your postcode in Government Gateway or GOV.UK Verify.
• Once you are registered to use the system, you will need all your tax records, dividend vouchers, receipts and other information in order to complete the online form.
• You can save your progress at any time and return to complete the form at a later date. If you’re using accounting software, you can store your records there, meaning when you need them for your tax return, everything is there in one place. And it’s faster than having to go through a box of receipts.

Additional tax return tips

When completing your Self Assessment tax return, it’s important to be organised, otherwise your tax calculation might be incorrect and you might pay too much or too little tax by mistake.

Use a separate business bank account, as well as accounting software, to track your income and expenses throughout the year rather than leaving it all to the last minute.

Other tax return tips include:

• Keep good records of your bank statements and receipts.
• Have a good idea of what expenses you can claim back – they must be legitimate expenses.
• Know your filing deadlines. The deadline for paper returns is 31 October. Online tax returns need to be completed by midnight on 31 January. And tax must be paid by midnight on 31 January for the previous tax year ending 5 April.
• Make sure you allow enough time to complete and submit your Self Assessment tax return so you can avoid penalties.
• Ask for help from a professional (see below) or consult the HMRC website, which has plenty of free resources, such as webinars and help sheets.

How an accountant can help with Self Assessment

If Self Assessment sounds like an admin headache, there’s one easy way to make life easier: hire an accountant or tax professional.

Their professional fees are considered an expense and can be offset against the tax bill, meaning many sole traders effectively pay nothing to receive the service.

Most sole traders still do some of the day-to-day accounting work themselves, of course, such as tracking income and expenditure.

The use of accounting software makes this easy and can tie in automatically with the accountant’s systems, so there’s not even any need to send any data.

At the very least, they turn to the accountant to prepare their Self Assessment return as required.

Paul Donno, a certified accountant and director of 1st Accounts Online, says if you use an accountant to help with your Self Assessment tax return, they might be able to help you claim more tax relief.

He adds: “We know the things that you can claim for that you probably wouldn’t even think of, even if you use the HMRC website and their set rules.

“Another area we help with is avoiding errors.

“For example, a lot of people believe that the clothing they wear for doing their trade is an expense. Well, quite a lot isn’t.

“So, we help you avoid the many penalties for making errors on your returns – even if they’re innocent errors.

“Lastly, accountants are your trusted adviser. And when you’re in a position to grow your business, they can help you do that as well.

“A good accountant will be looking at your records, making sure they’re straight and talking to you about your business on a quarterly basis. That’s been a fantastic service for our clients.”

Final thoughts

It’s important not to panic if you have missed the 31 January deadline.

However, don’t delay, as the sooner you complete and file your tax return the better.

Unless HMRC waives any penalties (make sure to contact them, as highlighted above), the minimum you’ll have to pay in fines is £100.

But if you take too long, this figure will increase.

Mariah Tompkins from WKM Accountancy Services adds: “Overall, it’s important to remember that the sooner you act, the fewer fines you will incur. It is always better to act now instead of putting it off.

“Try to be as organised as possible: it’s never too early to start preparing for next year to avoid last-minute submissions.”

Editor’s note: This article was first published in February 2020 and has been updated for relevance.