With just over a week to go until the Self Assessment deadline on 31 January 2026, the pressure is now firmly on for millions of UK taxpayers who haven’t yet submitted their tax return. And if you miss this deadline, HMRC will automatically issue a £100 penalty, even if you don’t owe any tax.
But remember, there is still time to file accurately and avoid unnecessary fines. Here are three last-minute tips to help you get your Self Assessment Tax Return done in time.
Key Self Assessment Deadlines at a Glance
Action | Deadline |
|---|---|
Online Tax Return Submission | 31 January 2026 |
Tax Payment | 31 January 2026 |
Interest Starts | 1 February 2026 |
First Late-Payment Penalty | 2 March 2026 (for 30 days late) |
Tip 1: Get Your Numbers Ready & Check Everything Carefully
Before beginning to file your Self Assessment, gather all your income and tax records. Rushing this step is one of the most common causes of mistakes.
Make sure you have:
- Your P60 and/or P11D if you are employed
- Records of self-employment income and allowable expenses
- Details of bank interest, dividends and rental income
- Information about any other untaxed income
Once you have all the information you need, you may begin entering the relevant figures into HMRC’s online Self Assessment system. But, while doing that, take your time and review each section carefully before moving on.
Mistakes can lead to HMRC enquiries, need for amendments or penalties. Accuracy now saves problems later.
Tip 2: Wait for HMRC Confirmation Page
A surprisingly high number of taxpayers complete most of their Self Assessment Tax Return but fail to actually submit it. It is very important to note that until you see HMRC’s confirmation page, your return is not legally filed.
Remember, the deadline is midnight on 31 January and you must submit the return and pay any tax owed by that date.
Late Filing Penalties If You Miss the Deadline
Delays | Penalties |
|---|---|
Missing the deadline day | £100 instant penalty |
Up to 90 days | £10 per day |
Another 90 days | £300 penalty or 5% of the tax you owe, whichever is greater |
If you still have not filed it within a year | £300 penalty or 5% of the tax you owe, whichever is greater |
Intentionally delaying your filing | Up to 100% of owed tax |
Filing late and paying late are treated separately by HMRC. You can still be penalised even if you owe no tax.
In Your Haste to File Your Self Assessment Tax Return, Don’t Fall Victim to Scams
With the 31 January 2026 Self Assessment deadline approaching, be cautious of emails, calls or texts claiming to be from HMRC. HMRC will never ask for your password, PIN or full bank details, and all tax payments must be made through official channels.
Tip 3: Seek Professional Guidance
If you’re unsure about what to include (for example, allowable expenses, side income or rental profits) getting advice from qualified experts can prevent costly mistakes.
That said, last-minute professional help can be more expensive, as advisers are extremely busy close to the deadline. So, the sooner you act, the better.
But My Problem Isn’t Filing My Self Assessment Tax Return, It’s Making My Tax Payment
If you can’t afford to pay your full tax bill by the 31 January deadline, don’t worry. There is help available. HMRC offers a Time to Pay (TTP) arrangement that allows you to spread payments over time, but you must submit your return first.
Scenario | What to Do | Key Condition |
|---|---|---|
You can't pay your full tax bill | Apply for HMRC's Time to Pay | You must file your return |
You owe £30,000 or less in taxes | Apply for TTP online | You get up to 12 months to pay |
You owe more than £30,000 | Call HMRC | You must set up a custom payment plan |
Conclusion
With 31 January now just a week away, there’s no time left to delay your Self Assessment return. Staying organised, double-checking your figures and making sure you formally submit and get the confirmation screen before midnight are the keys to avoiding penalties and unnecessary stress.
If you haven’t started yet, gather your paperwork today and work through the online form methodically. Even if you can’t pay your full tax bill immediately, filing on time gives you access to HMRC’s Time to Pay options and prevents automatic late-filing penalties.
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