Self Assessment deadlines: When to register, file and make a payment in 2023/24

Read this guide to learn when you need to register for Self Assessment, submit a return, and pay your tax bill.

Partner holding tablet device smiling.

Filing a Self Assessment Tax Return can be a stressful time if you’re self-employed.

Keeping track of the key dates and deadlines, managing accounting records, and making sure you’ve paid your tax bill on time is no easy task.

In this short guide, we’ve compiled all of the key dates and deadlines for Self Assessment in the UK. We share the deadline for registering for Self Assessment and submitting a return, and the HMRC payment deadlines – so you can stay on top of your tax obligations.

5 October 2023: Self Assessment tax registration deadline

The HMRC Self Assessment registration deadline is 5 October. You must let HMRC know by this date if you need to file a tax return. You can do this via the Self Assessment registration form on the HMRC site.

For example, if you need to file a return for the tax year 2022/23, you should register for Self Assessment by 5 October 2023.

This is the deadline for letting HMRC know you have income that hasn’t already been taxed before you received it, or capital gains above the annual exempt amount, which is:

  • £12,300 for 2022/23
  • £6,000 for 2023/24

This is so HMRC can send you a notice to file a Self Assessment Tax Return.

If you’re wondering ‘how long does Self Assessment registration take?’, head down to the FAQs at the bottom of this page.

31 October 2023: Self Assessment deadline for paper tax return

If you’re submitting a paper tax return to HMRC, this must be filed by 31 October.

Sending a paper return after this date could mean you incur a penalty – even if you have no tax to pay. If you want more time to prepare your Self Assessment Tax Return, opt for filing online instead. The deadline for online tax returns is 31 January.

In the coming years, paying income tax is going digital. Self-employed people and landlords will need to submit their returns using HMRC-recognised software, under Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) rules. But you can get ahead of the legislation and enjoy a smoother transition, by switching to cloud-based software now.

Read our guide on MTD deadlines for more details on the ITSA timeline.

30 December 2023: Deadline to let HMRC know to collect Self Assessment payments through PAYE

In some cases, HMRC can collect your tax payments through your PAYE tax code, over 12 months. But you’ll need to meet the following criteria:

  1. You owe less than £3,000 (in full – this cannot be a part-payment)
  2. You already pay tax through PAYE (e.g. you’re an employee or you receive a company pension)
  3. You submitted a paper tax return by 31 October, or an online return by 30 December

You can find the full criteria on the HMRC payment deadlines page.

31 January 2024: Online tax return payment and filing deadline

31 January is often a late night for small business owners, accountants and bookkeepers.

This is the deadline for filing an online tax return and paying what you owe, following the tax year end ( 5 April).

For those who make payments on account (advance payments to cover your next tax bill), 31 January marks the first of two self employed tax payment dates.

You may find some details are already filled in on your Self Assessment Tax Return. HMRC pre-populates certain information throughout the year – such as state and occupational pension. But you’ll need to fill in the rest using your own records.

31 July 2024: Second online Self Assessment payment deadline

If you make payments on account, the deadline for making your second payment is 31 July. This payment, along with your first payment on account made in January 2024 will be taken off your tax liability for the 2023/24 tax year.

Check out the HMRC guidance on self employed tax payment dates for more help.

How to file Self Assessment Tax Returns

For now, you can file a Self Assessment Tax Return online or on paper.

Making Tax Digital for self-employed people is set to change the Self Assessment process. Keeping digital records and submitting returns using HMRC-recognised software will become mandatory under MTD for ITSA rules, beginning in April 2026. You’ll no longer be able to use the online system or paper returns.

So if you’re already keeping digital records in HMRC-recognised software, you’re one step ahead of the ITSA legislation. For the full details, read our guide on how Self Assessment Tax Returns are changing: MTD for ITSA.

Self Assessment FAQs

What happens if you miss the Self Assessment registration deadline?

If you miss the deadline, you could be subject to a penalty. Register as soon as possible and let HMRC know immediately. You can learn more about failure to notify penalties on the HMRC site.

If you fail to submit a return on time or pay your self-employment tax, you could be subject to a range of penalties. Learn what happens if you don’t pay self-employment tax in our guide.

H3: How long does Self Assessment registration take?

You can register for Self Assessment in a few steps.

  1. Head to’s ‘Register for Self Assessment’ page. Click ‘Start now’
  2. Complete the questions. HMRC will tell you on the final page if you need to register for Self Assessment and file a tax return
  3. On the final page, read the guidance on ‘How to register’. You can register through your business tax account – you’ll either need to sign up for or sign into your Government Gateway account
  4. After signing up through your business tax account, you’ll be sent a Unique Taxpayer Reference number (UTR) via post
  5. HMRC will let you know via email or post when to file a Self Assessment Tax Return.

Submitting a return is a swift process if you’ve been keeping accurate records throughout the tax year. Cloud-based software such as Xero or Xero Go can help you keep on top of tax compliance and save hours on manual admin.


Xero does not provide accounting, tax, business or legal advice. This guide has been provided for information purposes only. You should consult your own professional advisors for advice directly relating to your business or before taking action in relation to any of the content provided.

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