Self Assessment Tax Return Deadlines

Self Assessment Tax Return Deadlines

Key Dates You Need to Know for Filing Your Tax Return

When it comes to Self Assessment, missing a deadline can be costly. Each year, many taxpayers often get caught out simply because they were not aware of the key dates, or, they left things a little too late.

In this blog, we break down the most important Self Assessment tax return (SATR) deadlines and how to taxpayers can keep on track of their obligations.

The Self Assessment Tax Year

The tax year runs from 6 April to 5 April the following year. Your Self Assessment tax return reports income earned during this period.

For example, the tax return due by 31 January 2026 covers income earned between 6 April 2024 and 5 April 2025.

Key Self Assessment Deadlines

5 October – Register for Self Assessment

If you’re filing a tax return for the first time, you must register with HMRC by 5 October following the end of the tax year.

Missing this deadline can delay your ability to file and may result in penalties.

31 October – Paper Tax Return Deadline

If you choose to file a paper tax return, it must reach HMRC by 31 October.

30 December – Paying through your Tax Code

For individuals wishing to pay their self assessment tax through their tax code, they need to submit their tax return online by 30^th December.

31 January – Online Tax Return & Payment Deadline

This is the most important date for most taxpayers.

By 31 January, you must:

• – Submit your online Self Assessment tax return
• – Pay any tax owed for the previous tax year
• – Make your first payment on account, if applicable

Failure to meet this deadline will result in an automatic £100 late filing penalty, even if you have no tax to pay. Furthermore, interest can be charged on late payments along with additional fines where delays continue.

Payments on Account: What You Need to Know

If your tax bill is over £1,000 and less than 80% of your tax is deducted at source, HMRC may require payments on account.

These are advance payments towards your next tax bill and are due:

• – 31 January – First payment on account
• – 31 July – Second payment on account

How to Stay on Track with Self Assessment

To avoid last-minute stress, it’s important to gather your income and expense records early and always seek professional help if you are unsure.

An accountant can ensure your return is submitted correctly and on time and help you understand exactly what you owe.

Need Help Submitting your Tax Return?

If you’re approaching the deadline and have not yet filed your tax return, there’s still time to act.

We can help you prepare and submit your Self Assessment tax return and help advise you on payments on account.