Firstly, beware of scams

Be aware of the risk of falling victim to scams that mention HMRC and tax returns. Never share your HMRC login details with anyone. HMRC provides advice on how to identify and deal with scams.

When is the Self Assessment tax return deadline?

This depends on how you submit your return:

• For paper tax returns, the deadline is October 31st 2025.
• For online tax returns, the deadline is January 31st 2026.​​​​​​

Important: January 31st 2026 is also the deadline for paying any tax owed. There’s usually a second payment deadline of July 31st if you make advance payments towards your bill (known as ‘payments on account’).

Penalties for late filing and paying tax owed

Penalties for late filing start with a fixed £100 penalty, with greater financial penalties coming after 3, 6 and 12 months, depending on how late the return is filed. There are also penalties for paying any tax owed late, with interest also charged on any tax paid late.

Check if you need to send a Self Assessment tax return

If you're not sure if you are still required to complete a Self Assessment return, you can check via this online tool and learn more details here.

People who sell via online marketplaces such as eBay and Etsy may also need to complete a tax return if they sell 30 items or more a year or have total earnings over £1,700. 

How to submit your tax return

People can submit their tax returns and pay any tax owed by logging into their Government Gateway account on GOV.UK. You'll also need your Unique Taxpayer Reference number.

For details on how to log in, or how to set up a Government Gateway account if you have yet to do so, visit the 'File your Self Assessment tax return online' page on GOV.UK.

Are you completing a tax return for the first time?

You must tell HMRC by 5th October 2025 if you need to complete a tax return for the previous tax year and you have not sent one before. If you tell HMRC after 5th October 2025, you could get a penalty.

You can tell HMRC by registering for Self Assessment here.

If you register after 5th October 2025, HMRC will send you a letter or email with a different deadline to send your tax return by - this will be 3 months from the date on the letter or email. 

If you didn't send a tax return last year

If you’ve registered for Self Assessment before but did not send a tax return last year, you must register again to reactivate your account.

Are you a sole trader? Check what taxes may apply to you

Aimed at supporting new and existing sole traders to better understand their responsibilities, a new interactive tool from HMRC explains the records they may need to keep, taxes that may apply to their business, and other useful information such as how to pay a tax bill.

If you want the tax you owe to be collected from your wages or pension

You must have submitted your online return by December 30th if you want HMRC to automatically collect tax you owe from your wages and pension. Find out if you are eligible to pay this way.

Need help with your tax return?

There are lots of tools and resources available to help, including: 

• HMRC's digital assistant  - the assistant will help you find information, and if you can’t find what you’re looking for you can ask to speak to an adviser
• Guidance notes and help sheets with a wealth of information
• A series of video tutorials
• Live and recorded webinars:
  • New to Self Assessment: an introduction
  • New to Self Assessment: budgeting and payments
  • Starting your online tax return
  • Filling out the self-employment section of your tax return
  • Filling out the employment section of your tax return
• Download the HMRC app
• Subscribe to HMRC email updates for the latest information on Self Assessment

Do you need technical support?

Find technical support for help signing into HMRC online services.

Do you need extra or specialist support?

You can get extra support if your personal circumstances make dealing with taxes and tax returns difficult. For example, if:

• you have dyslexia, autism or cognitive difficulties
• you have reduced mobility or physical disabilities
• you have sensory disabilities, like a visual, hearing or speech impairment
• you have mental health conditions, like depression, stress or anxiety
• you’re experiencing financial hardship - for example you cannot afford essentials like food, bills or rent (you may be able to pay in instalments)
• you’re a victim of domestic abuse, including economic abuse
• you're a refugee or migrant
• English is not your first language and you require an interpreter
• you’re receiving treatment in hospital

For support on the above, you can contact a voluntary or community sector organisation who can provide you with help and advice, or contact HMRC via the links here.