The self-assessment deadline is fast approaching. If you are self-employed, a landlord, or earning untaxed income, you are probably thinking about getting your tax return in before the 31st of January.
At Brisan Accountancy, we know that many people have the same questions every year; so we have put together this quick FAQ-style guide to help you stay ahead of the deadline, avoid penalties, and keep your finances clear.
When is the self-assessment deadline?
The filing and payment deadline is 31st of January 2026. That means:
- Your tax return must be submitted by this date
- Any tax owed must be paid in full by this date
Missing this deadline could result in automatic penalties and interest. The earlier you file, the more time you have to plan your payment.
See how Brisan can help you file your self-assessment
What happens if I miss the deadline?
If you do not file your return or pay your tax on time, HMRC will issue penalties:
- £100 fixed penalty if your return is up to 3 months late
- Daily penalties if it remains unfiled after that
- Interest charges start immediately on unpaid tax
Even if you file your return on time but fail to pay the tax bill by 31st of January, interest still applies.
I’ve filed my return, do I still need to do anything?
Yes. Filing is only part one of the process. Once you have submitted your return, you must make sure the payment is arranged on time.
Check that you:
- Understand how much you owe
- Know whether payments on account apply
- Have a plan in place to pay before the deadline
If you are unsure what the final amount is, contact your accountant or log into your HMRC portal.
Need support reviewing your tax bill? Contact Brisan here
What are “payments on account” and do they apply to me?
Payments on account are advance payments towards next year’s tax. They are typically required if your tax bill is more than £1,000 and you have not already paid more than 80% through PAYE.
There are two instalments:
- 31st of January 2026
- 31st of July 2026
Many people are surprised to see their bill is effectively doubled. Make sure to check if your return includes this.
I can’t afford to pay, what should I do?
If you are struggling to pay your tax bill, do not ignore it. HMRC offers a “Time to Pay” arrangement that allows you to spread the cost.
To be eligible, you must:
- File your return before the 31st of January
- Owe less than £30,000
- Apply online or speak to HMRC directly
The sooner you apply, the better your chances of avoiding further penalties.
Learn more about managing tax payments with Brisan
How can I avoid this stress next year?
The best way to avoid a January panic is to make self-assessment part of your regular routine.
Here are a few ways you can stay ahead:
- Keep on top of your bookkeeping
- Set aside tax throughout the year
- Use cloud accounting software to track your profits
- Work with an accountant who helps you plan ahead
Brisan Accountancy offers cloud accounting solutions that make it easier to log expenses, raise invoices, and track income as you go.
Is it too late to get help now?
No, but you should act quickly. Even if you have left it until January, there is still time to get organised and avoid penalties, but every day counts.
We regularly help clients across Kent with last-minute returns, payment queries, and HMRC communications. If you are feeling overwhelmed, it is better to ask now than to wait.
Speak to our team today and we will help you get sorted.
Final Word
The 31st of January is a firm deadline, but it does not have to be stressful. With the right support and a clear checklist, you can get your return filed, payment made, and move into February with peace of mind.
At Brisan, we are here to help you make tax simpler — not more stressful. If you need advice, practical support, or just someone to make sense of the numbers, our team is ready.
