What You Need to Know Before 31 January 2026

The Self Assessment tax return deadline for the tax year ending 5 April 2025 is 31 January 2026. By this date, you must both file your tax return and pay any tax due. Missing the deadline can result in automatic penalties, even if no tax is ultimately payable.

Although the deadline feels far away, you do not need to wait until January to file. In fact, filing early is often the most practical and cost-effective approach.

Why filing on time matters ?

Submitting your Self Assessment tax return before 31 January 2026 gives you clarity and control. You will know exactly how much tax is due, whether a payment on account applies, or whether you are entitled to a refund. Early filing also makes budgeting easier and avoids last-minute pressure when many taxpayers rush to meet the deadline.

Importantly, if there are errors or missing information, filing early leaves time to correct them without penalty.

Penalties you should be aware of

If you miss the 31 January deadline, a £100 late filing penalty is charged automatically. This applies even if you owe no tax or have already paid. Further penalties can apply if the return remains outstanding, including daily fines and additional charges based on the tax due.

Late payment of tax can also result in interest and surcharges, which increase the longer the balance remains unpaid. These costs are avoidable with proper planning.

Common Self Assessment pitfalls

Many taxpayers fall into avoidable traps, such as:

• Assuming no return is needed because no tax is payable
• Missing income from overseas, property, or side activities
• Forgetting to register for Self Assessment when filing for the first time
• Leaving filing until January and discovering information is missing

If HMRC has issued you with a notice to file, you must submit a return — regardless of your income level.

Timeline for Paying your tax

Any tax owed must be paid by 31 January 2026. If payment in full is not possible, it is essential to address this early. Leaving it until the deadline limits your options and increases the risk of penalties and interest.

Final Words About Self Assessment Tax return 2024-2025

The Self Assessment deadline is fixed, but the pressure is optional. Filing early helps you stay compliant, avoid penalties, and make informed financial decisions. If you are unsure whether you need to file, how much tax you owe, or how to prepare properly, professional advice can make the process far simpler and safer.

Seek Accountant's Help for Your Tax Return

Given the October rush, it’s more important than ever to have reliable support. If you’re unsure about whether you need to file, how to report specific income types, or you want peace of mind your return is done correctly and on time — Elaga Accountancy can help.

We’ll handle your registration, confirm your UTR, prepare your return, and send it on your behalf so you’re compliant and penalty-free.

Don’t wait until the last minute and risk being caught out. Let us take the stress away — you’ll know your affairs are in order, and you’re meeting your legal duty to file and pay.

***Contact us to learn more.

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