What is the tax return deadline in the UK?

If you earn untaxed income as a self-employed individual or from rental properties, it’s important to complete and submit a self-assessment tax return every year and meet the UK tax return deadline. If you don’t, you could be subject to penalties. On this page, you’ll learn about the updated self-assessment deadline, what may happen if you miss the deadline and the key dates you need to know this tax year.

The information provided here is for informational and educational purposes only and does not constitute financial advice. Please consult with a licensed financial adviser or professional before making any financial decisions. Your financial situation is unique, and the information provided may not be suitable for your specific circumstances. We are not liable for any financial decisions or actions you take based on this information.

If you need to complete a tax return, the deadline for submitting it for the UK tax year 2025/26 (6 April to 5 April) is midnight on 31 October 2026 for paper returns, or 31 January 2027 for online returns (you might also be eligible to claim tax relief when you submit your tax return).

The only time the tax return deadline in the UK may change is if you received notice from HMRC telling you to submit an online tax return after 31 October 2026. In that case, you’ll have three months to submit your tax return from the date of notice. 

If you still owe tax from your 2024/25 income, it should be settled when you make your first payment.

Yes, you have to pay self-assessment tax by the 31 January. The deadline to file your tax return and pay any tax due is 31 January following the end of the tax year. If you owe tax, you must pay it by this date to avoid penalties.

If you fail to submit your tax return on time, you could receive the following penalties:

• You can be charged a fee for paying tax just one day past the self-assessment deadline.
• If you pay later than three months after the tax self-assessment deadline, you could be penalised up to £1,000.
• If you pay your tax bill between six and 12 months late, you may have to pay an additional £300 on top of your earlier fines. In some cases, you may be fined 5% of your tax bill, which can be more expensive.
• If you pay more than 12 months late, you’ll be subject to another £300 fine or 5% of your tax bill, including all other penalties. In more serious cases, you can be fined 100% of the tax you owe on top of your original tax bill.

The following are important tax return dates you may want to keep in mind:

• 6 April 2026: The first day of a new tax year. Depending on the UK government’s budget, new tax rates and allowances are implemented from this day.
• 31 July 2026: If you’re self-employed, you’ll need to make your second payment for your tax bill from the previous year on account by midnight on 31 July.
• 5 October 2026: If you’ve never submitted a tax return before, you’ll need to register for self-assessment by 5 October 2026 to file a return for the 2025/26 tax year. When you submit a tax return for the first time, you receive a Unique Taxpayer Reference (UTR) number and an activation code that allows you to file your returns.
• 31 October 2026: The deadline to submit your tax return for the year ending 5 April 2026 in paper format. If you’ve received notice from HMRC that you need to file a tax return after 31 July 2026, you’ll need to complete your return within three months of the date on your notice.
• 31 January 2027: Online self-assessment tax returns for tax year 2025/26 must be submitted by this date.
• 5 April 2027: The end of the tax year 2026/27.

The end of the tax year is generally more important for those who are self-employed or registered as a sole trader, rather than people who are employed by companies. This is because self-employed people and sole traders are responsible for paying their own taxes and submitting their earnings through a process called self-assessment.

However, even if you are a salaried employee and earn your income via PAYE (Pay As You Earn), there are also a few instances where you might need to file a tax return, including if you:

• Earn more than £1,000 from a side business or hobby
• Are the landlord of a property and earn money from rent
• Have income from savings or investments over a certain threshold
• Receive tips or commission
• Receive over £1,000 in dividends and need to pay tax
• Need to pay the High Income Child Benefit Tax Charge
• Also earn overseas income

Find out whether you need to complete a tax return with our handy guide to the tax return.

The official self-assessment deadline for filing your documents for the tax year ending April 5 (and for paying any money due) is midnight on 31 January. This is always the January after the year in question. So for the 2025/26 tax year (which ended 5 April 2026), you need to file your tax return by 31 January 2027.

You can start your self-assessment tax return for the 2025/26 tax year, which ends on 5 April 2026, as soon as the online service is available, typically from early April 2026.

The deadline to submit your online tax return and pay any tax due for the 2025/26 tax year is 31 January 2027.

You can technically submit your self-assessment as late as 31 January of the following year, but it’s best to file and pay as early as possible to avoid penalties and interest. For late payments, interest will be charged on any tax owed, starting from 1 February.

You will have to pay a late filing penalty of £100 if your tax return is up to 3 months late. If you are over three months late in sending your self assessment, you will be a charged a daily penalty of £10 per day, to a maximum of £900.

After 6 months, a further penalty of 5% of the tax due or £300 (whichever is greater) may be applied.

From 6 April 2026, sole traders and landlords with annual income over £50,000 from self-employment and property must use HMRC’s Making Tax Digital for Income Tax to report their income and expenses. 

Taxpayers who fall into this category will need to use software that works with Making Tax Digital for Income Tax to create and store digital records of self-employment and property income and expenses, send quarterly updates to HMRC and submit their tax return by 31 January. 

You can read more about Making Tax Digital for Income Tax, including a step-by-step guide, on the Gov.uk website.