When are self-assessments due for submission?

Jun 30, 2023 | Business tax, Personal tax

We’d be very rich accountants if we had £1 for every time someone asked us “when are self-assessments due?”.

And after our most recent blog post, where we examined how long you need to keep self-assessment tax records as a UK business, we thought now is the right time to give more guidance on the submission deadline and how to get ahead of it before it’s too late.


When is the self-assessment deadline?

If you’re a sole trader, you’ll have to remember your upcoming deadlines for your self-assessment tax return.

And there are several key deadlines to be aware of, rather than just one for everything. Don’t worry, there’s still plenty of time before the first key self-assessment date hits your calendar.


To register

If you’re new to self-assessment, you must register with HMRC by 5 October 2023 for the 2022/23 tax year.

There are different ways to register depending on your status, but whatever business type you are, you must register online via the GOV.UK website.


To pay via paper tax return

You have until midnight on 31 October 2023 for your paper tax return deadline.

HMRC must receive it by this date, so send it off with plenty of time to spare, as filing a paper return always takes longer.


To pay online

For online payments and returns, you’ll have until midnight on 31 January 2024 to submit. This is also the deadline to pay the tax you owe and make your first payment on account if relevant.

But if you want HMRC to automatically collect the tax you owe through your tax code, then you’ll need to submit your return by 30 December 2023.

And by 2026, many self-assessment tax returns will be done online as part of Making Tax Digital (MTD) for ITSA.


Other deadlines to be aware of

  • 5 April 2023 — end of the UK tax year
  • 31 July 2023 — second payment on account deadline


How much is the fine if I miss the self-assessment filing deadline?

HMRC automatically applies a £100 penalty to anyone who fails to file a return by the deadline — if you have an online account, this penalty will be added automatically.

It does not matter if you owe tax or not: in the event that you fail to file your tax return within three months — that is, by the end of April — then HMRC can impose an additional £10 daily penalty for the next 90 days, bringing the total penalty to £1,000.

If you owe a particularly large amount, additional penalties may be imposed after six and 12 months — based on the amount of tax you owe.

And on top of these penalties, you’ll be charged interest on any unpaid tax.


Talk to an expert

With the digital tax return soon becoming mandatory for a large number of self-assessment taxpayers, it can feel like there are a lot of changes to the tax system to keep up with.

But the deadlines stay the same every year, and if you’re already filing your tax online, it’s a lot easier to stay on top of.

For all tax returns and self-assessment enquiries, contact an expert like us as soon as possible. We’ve seen it all and can talk you through your tax problems step by step.

Get in touch with us today to talk about your self-assessment tax return.

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