Self Assessment Tax Return Deadlines UK
If you are required to complete a Self Assessment Tax Return in the UK, knowing the key HMRC deadlines is essential. Missing a filing or payment deadline can result in penalties, interest and unnecessary stress. Whether you are self-employed, receive rental income or have other income that needs to be reported through Self Assessment, staying organised can make the process considerably easier.
The UK tax year runs from 6 April to 5 April of the following year. Once the tax year has ended, taxpayers who need to complete Self Assessment generally have several months to organise their financial records, calculate their income and expenses and prepare their tax return.
For the 2025–26 tax year, which ended on 5 April 2026, one important date is 5 October 2026. This is generally the date by which you should notify HMRC if you need to complete a Self Assessment Tax Return and have not previously registered or been required to file.
If you choose to submit a paper Self Assessment Tax Return, HMRC must normally receive it by 31 October 2026. Most taxpayers now submit their returns online, and the normal online filing deadline for the 2025–26 tax year is 31 January 2027.
The 31 January 2027 deadline is also normally the date by which any balancing payment of Self Assessment tax for the 2025–26 tax year must be paid. This means it is important to consider both your filing responsibility and the amount of tax you may need to pay.
Some taxpayers are also required to make payments on account towards their next Self Assessment bill. Where payments on account apply, the first payment is generally due on 31 January, with the second payment due on 31 July. These advance payments are normally based on the previous year’s tax liability and can significantly affect how much money you need to have available at each deadline.
HMRC can charge penalties when a Self Assessment Tax Return is submitted after the applicable deadline. A penalty can arise even if there is no tax to pay, and additional penalties may apply when a return remains outstanding for longer periods. Interest and late-payment penalties may also apply when tax is not paid on time.
One of the easiest ways to avoid missing a Self Assessment deadline is to start preparing your return well in advance. Keeping your financial information organised throughout the year means you will not have to search for important records shortly before the filing deadline.
Useful records can include details of your business or self-employed income, allowable business expenses, invoices, receipts, bank statements, rental income, pension contributions and other relevant tax documents. Maintaining accurate digital bookkeeping records can make preparing your Self Assessment Tax Return much simpler.
Submitting your return early does not normally mean you have to pay your tax immediately. You can file your return before the deadline while still paying the amount due by the appropriate payment date. Filing early can therefore give you more time to understand your tax liability, budget for the payment and resolve any missing information before it becomes urgent.
Preparing early can be particularly helpful if you have several sources of income, significant business expenses, rental property income or payments on account. Knowing your expected liability in advance can make cash-flow planning easier and reduce the pressure associated with the January deadline.
Self Assessment does not need to be complicated. EasyFig can help organise your financial information, review allowable expenses, prepare your Self Assessment Tax Return accurately and help ensure important HMRC deadlines are not missed.
Need help with your tax return? Book a free consultation with EasyFig today.