Income Tax Returns: 5 Key Reasons You Should Submit Early

The final submission deadline for the Income Tax Returns is 31st January, following the end of the tax year. So, for the tax year that ended on 5th April 2025, the return must be submitted by 31 January 2026. For those filing paper Income Tax Returns, the deadline is far earlier, 31 October 2025.   

It is uncommon to find someone who looks forward to completing and filing their Self-Assessment Tax Returns. For many, and for various reasons, it is often something they put off for as long as possible, but it is important to outline why it may be beneficial to consider filing earlier, leading in some cases, to significant benefits.  

What are the benefits with early tax return submissions? 

1. More Time to Plan & Budget 

Where your last self-assessment tax bill was greater than £1,000, or you have tax deducted at source that amounted to less than 80% of your overall income tax liability, you are required to make advance payments towards the current year’s tax bill, which are payable in equal instalments in January and July each year. 

By filing your Tax Return before the second payment is due on 31 July 2025, you will be able to apply any reduction required to this payment, rather than paying the full amount now and having to claim a refund later in the year.  

For those who have significant changes to their income from one year to the next, it makes total sense to file early, allowing plenty of notice to save for the expected tax liabilities. For example, where income levels have increased, early filing avoids a large balancing tax payment becoming due with just a short window of time left to find the money to pay the liability.  

For cases where the July payment on account has already been reduced, confirming your tax liability well ahead of the payment date also prevents the possibility of any over-reduced Payment on Account on which late payment interest will be charged. 

2.Accelerate Your Tax Refunds 

For individuals who are set to be in a repayment position, an earlier filing means HMRC may process the repayment quicker, particularly before they experience capacity constraints as the filing deadline approaches. Repayments can take longer to process during busy periods, and therefore it is in the interest of those in a repayment position to submit their returns early.  

3.Avoid Last-Minute Stress & Mistakes  

By taking the time to collate your information and avoiding the rush of an impending deadline, there is less chance that information is missed. Mistakes can be costly and if HMRC discovers that careless errors have been made, they may impose a charge of up to 30% of the extra tax due – more if it relates to offshore sources. And remember, you can always amend your return right up to 31 January 2026 if you need to.  

4.Avoid Penalties & Interest 

Late filing of your tax return and late payment of your tax can result in considerable fines and interest charges. HMRC have outlined that the penalty for missing the 31 January deadline is an immediate £100, which increases over time. Additionally, interest is charged on any unpaid tax from the due date until payment is made. Therefore, filing early ensures you can avoid these unnecessary costs.  

5.Access to Professional Advice 

Tax advisors and accountants are often inundated with last-minute requests as the January deadline approaches. By seeking assistance early, you’re more likely to secure the time and attention of a professional, ensuring your return is carefully reviewed to optimise available reliefs and deductions. Early filing provides the opportunity to take full advantage of tax planning strategies that can minimise your liability.  

If you have any questions regarding your Self-Assessment Tax Return, please do not hesitate to get in contact with Emily Robson, or a member of our Private Client Team who would be more than happy to help.