Tax Year Dates & Deadlines: A Complete Guide 2026

Missing an important tax deadline can lead to penalties, interest charges, and unnecessary stress. Whether you're self-employed, a landlord, an employer, or required to file a Self Assessment tax return, knowing the key UK tax dates helps you stay organised and meet your HMRC obligations on time.

The UK tax year 2026/27 runs from 6 April 2026 to 5 April 2027. Important deadlines include 31 July 2026 for the second payment on account, 31 October 2026 for paper tax returns, and 31 January 2027 for online Self Assessment filing and tax payment.

This guide explains the key UK tax dates and deadlines for 2026/27, what each deadline means, who it applies to, and how to avoid late filing penalties. 

Why Is It Important to Know Tax Year Deadlines?

Missing tax deadlines can lead to:

• Late filing penalties
• Interest on unpaid tax
• Additional HMRC charges
• Cash flow problems
• Unnecessary stress

Planning makes tax management much easier and helps you avoid costly mistakes.

Tax Year Dates & Deadlines 2026

Here are the main tax dates to remember during the 2026/27 tax year.

Date	Deadline	Who It Applies To
6 April 2026	Start of 2026/27 tax year	Everyone
31 July 2026	Second payment on account for 2025/26 Self Assessment	Self-employed & taxpayers making payments on account
5 October 2026	Register for Self Assessment (if newly self-employed or required to file)	New taxpayers
31 October 2026	Deadline for paper Self Assessment tax returns	Self Assessment taxpayers
30 December 2026	Online tax return deadline if you want tax collected through PAYE (where eligible)	Employees & pensioners
31 January 2027	Online Self Assessment tax return deadline	Self Assessment taxpayers
31 January 2027	Pay Self Assessment tax bill	Self Assessment taxpayers
31 January 2027	First payment on account for 2026/27	Self-employed & taxpayers making payments on account
5 April 2027	End of 2026/27 tax year	Everyone

 

6 April 2026 - Start of the New Tax Year

The new tax year officially begins on 6 April 2026.

From this date:

• New tax allowances apply.
• New income starts counting towards the 2026/27 tax year.
• Businesses should start keeping records for the new tax year. 
• Any tax rule changes introduced for the year generally take effect.

This is also a good time to review your bookkeeping and financial records.

31 July 2026 - Second Payment on Account

If you're self-employed and make payments on account, the second instalment for your 2025/26 tax bill is due on 31 July 2026.

Payments on account help spread your tax bill over the year.

You usually need to make these payments if your previous tax bill was over a certain threshold and most of your tax  was not collected through PAYE.

5 October 2026 - Register for Self Assessment

If you have recently become:

• Self-employed
• A landlord with taxable rental income
• A partner in a business partnership

You normally need to register for Self Assessment by 5 October 2026, following the end of the tax year in which you became liable to pay tax.

Registering early gives you enough time to receive your Unique Taxpayer Reference (UTR) and prepare your return.

31 October 2026 - Paper Tax Return Deadline

If you choose to submit a paper Self Assessment tax return, it must reach HMRC by 31 October 2026.

Many people now file online because it:

• Gives more time
• Calculates tax automatically
• Reduces calculation errors
• Confirms successful submission immediately

30 December 2026 - PAYE Collection Deadline

Some employees and pensioners can have their Self Assessment tax collected through their PAYE tax code.

To qualify, you generally need to:

• Submit your online return by 30 December
• Owe less than the PAYE collection limit
• Meet HMRC's eligibility requirements

This allows tax to be collected gradually through salary or pension payments instead of paying it as a lump sum.

31 January 2027 - The Biggest Tax Deadline

For many taxpayers, 31 January is one of the most important tax deadlines of the year.

By this date, you must:

• Submit your online Self Assessment tax return
• Pay your tax bill for the previous tax year
• Make your first payment on account for the current tax year (if required)

Missing this deadline can result in:

• An immediate late filing penalty
• Interest on unpaid tax
• Additional penalties if the delay continues

Setting reminders well before January helps avoid last-minute problems.

5 April 2027 - End of the Tax Year

The tax year ends on 5 April 2027.

After this date:

• You should ensure all records are complete.
• Businesses should prepare accounts where required.
• You can begin preparing your Self Assessment return.

Good record-keeping throughout the year makes tax filing much easier.

Key Employer Tax Deadlines

If you employ staff, there are additional payroll deadlines to remember.

Deadline	Requirement
Every payday	Submit Full Payment Submission (FPS) through PAYE
Monthly	Pay PAYE Income Tax and National Insurance to HMRC
Quarterly (if eligible)	PAYE payments
6 July (following tax year)	Submit forms such as P11D where required

Using payroll software can help automate submissions and reduce errors.

Making Tax Digital (MTD) Updates in 2026

From 6 April 2026, Making Tax Digital (MTD) for Income Tax applies for many self-employed individuals and landlords with qualifying income above the relevant threshold.

Eligible taxpayers will generally need to:

• Keep digital records
• Use compatible software
• Submit quarterly updates
• Send a final declaration after the tax year ends

If MTD applies to you, preparing in advance can help you meet the new requirements more easily.

Common Tax Deadline Mistakes

Many taxpayers miss important deadlines due to avoidable errors. These mistakes can lead to penalties, interest charges, and unnecessary stress. Being aware of the most common errors can help you stay compliant and avoid extra costs.

Here are some common tax deadline mistakes to avoid:

• Leaving your tax return until the last minute, which increases the risk of errors or missing the filing deadline.
• Forgetting payment on account deadlines, resulting in late payment interest and possible penalties.
• Failing to keep receipts and financial records, making it difficult to complete an accurate tax return.
• Registering for Self Assessment too late, which may delay receiving your Unique Taxpayer Reference (UTR) and affect your ability to file on time.
• Assuming someone else has submitted your tax return without checking that it has actually been filed.
• Ignoring letters, emails, or reminders from HMRC, which may contain important information about your tax obligations or upcoming deadlines.

Planning ahead, maintaining accurate records, and setting reminders for key tax dates can help you meet your obligations on time and avoid unnecessary penalties.

Conclusion

Understanding the Tax Year Dates & Deadlines UK 2026 helps you stay organised and avoid unnecessary penalties. From the start of the tax year on 6 April 2026 to the online Self Assessment deadline on 31 January 2027, every key date plays an important role in meeting your tax responsibilities.

Creating a calendar of tax deadlines, maintaining accurate financial records, and filing your returns early can make tax season much less stressful and help you stay compliant with HMRC requirements.

Need Help With Your UK Tax Deadlines? Speedia accountants can help you manage your tax records, Self Assessment, and key HMRC deadlines. Contact Speedia today for simple, reliable tax support.

Frequently Asked Questions

1. What are the deadlines for filing tax returns in the UK?

Ans: Paper tax returns are due by 31 October, while online Self Assessment tax returns must be filed by 31 January.

2. Why does the UK have a 5 April tax year?

Ans: The current UK tax year dates back to historical changes to the calendar and has remained in place following subsequent calendar reforms.

3. What are the dates for each tax year?

Ans: The UK tax year always runs from 6 April to 5 April of the following year.

4. What happens if I miss the Self Assessment deadline?

Ans: HMRC may charge late filing penalties, interest on unpaid tax, and additional penalties if the delay continues.

5. Who needs to register for Self Assessment?

Ans: Self-employed, certain landlords, business partners, company directors in some circumstances, and others with untaxed income may need to register.

6. How can I avoid missing tax deadlines?

Ans: Keep accurate records, use reminders or accounting software, and submit your returns well before the deadline.