31 October 2025: Self-Assessment Deadline for Paper Tax Returns

🗓️ Important Date: 31 October 2025

 

If you intend to file a paper self-assessment tax return, you must submit it to HMRC by 31 October 2025. Failing this can result in penalties, interest, and unwanted stress-but with careful preparation or professional guidance, it is easy to stay in compliance.

 

💡 What is a Self-Assessment Tax Return?

 

A self-assessment tax return is the method by which individuals and sole traders notify HMRC of their income, costs, and tax due. It's needed if you are:

 

• Self-employed or a sole trader.
• A business partnership partner.
• A company director earning untaxed income.
• An individual with a second income, for example, from property, dividends, or investments.

 

If you're not certain if you have to, you can check HMRC's guide here:

👉 Self-Assessment tax returns: who must complete one - GOV.UK

 

🧾 Important Dates for the 2024–2025 Tax Year

 

• 5 April 2025: End of tax year.
• 5 October 2025: Last day for registering for self-assessment if you have not done so before.
• 31 October 2025: Last day for submitting paper tax returns.
• 31 January 2026: Last day for online submission and payment of tax.

 

Further information is provided on the official government website:

👉 Self-Assessment deadlines – GOV.UK

 

📦 Why File by 31 October Paper Filing Date?

 

Paper filing your tax return early provides:

 

✅ No £100 late filing penalties.

✅ On-time processing ahead of the January rush.

✅ A clear conscience, with your taxes sorted.

✅ More time to arrange payments and control cash flow.

 

Common Mistakes to Avoid

 

• Omission of all income, particularly freelance or rental income.
• Failure to include allowable business expenses.
• Use of old forms.
• Submission of the return to an incorrect HMRC address.
• Not signing or dating the form.

💡 Tip: Use the most up-to-date SA100 form from HMRC's forms library!

 

How Fair View Accountants in Watford Can Help

 

Fair View Accounts specializes in providing a variety of services for individuals and small businesses, preparing and file tax returns in Watford and beyond. If you prefer to paper file, or need help switching to the online submission process, our team will ensure that your return is:

• Accurate
• On time
• Fully compliant with HMRC

 

→ Find out about our Self-Assessment Tax Return Services. 

→ Contact Fair View Accountants in Watford for specialist help.

 

🕒 Don't Leave It To The Last Minute!

 

It is still October, but preparing your paperwork in advance will relieve stress and minimize mistakes at the submission.

📞 Get in touch with us now so our accountants can help you to complete your 2025 tax return with confidence.

 

FAQs

 

Will I be able to send my tax return online after 31 October 2025?

Yes, the online deadline is 31 January 2026.

 

What happens if I miss the 31 October paper deadline?

You will have no choice but to file online, or you may incur a late filing penalty of £100 if you miss both deadlines provided by HMRC.

 

How do I register for self-assessment?

You can register online at HMRC: Register for Self-Assessment - GOV.UK.

 

Can Fair View Accountants deal with my tax return from start to finish?

Yes, we provide full-service tax filing services, including document preparation and submission.

 

What do I need to submit my return?

Records of income, records of expenses, P60/P45 forms, bank statements, and details of dividends.