UK Tax Return Deadlines 2025

As the new tax year progresses, understanding the UK tax returns deadline becomes increasingly important for both individuals and businesses. Whether you’re a self-employed professional, a limited company director, or managing a corporate entity, keeping track of HMRC deadlines can save you from unnecessary stress, penalties, and interest charges.

At Boobooks, we understand that navigating the UK tax system can feel complicated, especially when balancing multiple responsibilities. This guide will walk you through the key tax return deadlines for 2025, including self-assessment and corporate tax dates, along with helpful tips to ensure you never miss an important filing.

Why Meeting Tax Deadlines Matters

Missing a tax deadline in the UK doesn’t just lead to inconvenience, it can result in significant financial penalties and even affect your business reputation. HMRC takes deadlines seriously, and even a one-day delay can trigger automatic fines.

By understanding when tax returns are due in the UK and planning ahead, you not only avoid penalties but also gain valuable peace of mind. You’ll have more time to review your accounts, maximize deductions, and ensure your submission is accurate.

Whether you’re filing as an individual or as a business, staying on top of these dates reflects financial responsibility and professionalism.

Key Deadlines for Self-Assessment Tax Returns

If you’re self-employed, a freelancer, a landlord, or earning untaxed income, you’ll need to complete a Self Assessment tax return each year. Here are the crucial dates to remember for the 2024–2025 tax year (covering income earned between 6 April 2024 and 5 April 2025).

1. Registering for Self-Assessment
   If this is your first time filing, you must register with HMRC for Self Assessment by 5 October 2025. This step is essential because it allows HMRC to issue your Unique Taxpayer Reference (UTR) and activate your online account.

2. Paper Tax Return Deadline
   If you prefer to file a paper return, you must submit it by 31 October 2025. However, most people now choose to file online for convenience and additional time.

3. Online Tax Return Deadline
   The most important UK tax returns deadline for most taxpayers is 31 January 2026. This is the last date to file your online Self Assessment tax return for the 2024–2025 tax year.

4. Payment Deadline
   The 31 January 2026 date also applies to paying any tax you owe for the previous tax year. If you make advance “payments on account,” the second installment is due by 31 July 2026.

To summarize:

• Register for Self Assessment: 5 October 2025

• Paper return deadline: 31 October 2025

• Online return and payment deadline: 31 January 2026

• Second payment on account: 31 July 2026

Keeping these in your calendar can make all the difference between a smooth filing experience and unnecessary penalties.

Key Corporate Tax Deadlines

For limited companies, deadlines operate differently. Corporate tax depends on your company’s accounting period, so the dates are specific to when your financial year ends. However, the general structure remains consistent:

1. Filing Your Company Tax Return (CT600)
   Limited companies must file their Corporation Tax Return (CT600) within 12 months of the end of their accounting period.
   For example, if your accounting period ends on 31 March 2025, your return must be filed by 31 March 2026.

2. Paying Corporation Tax
   Corporation Tax payment deadlines are slightly earlier, you must pay any tax due within 9 months and 1 day after the end of your accounting period.
   Using the same example, if your financial year ends on 31 March 2025, your payment is due by 1 January 2026.

3. Annual Accounts and Confirmation Statement
   In addition to tax returns, you must also file your company’s annual accounts and confirmation statement with Companies House.

• Accounts: due within 9 months after your accounting year end.

• Confirmation statement: usually due every 12 months from your company’s incorporation date.
  

What Happens If You Miss a Deadline

HMRC is strict about late submissions. Missing a UK tax returns deadline can quickly add up in penalties:

For Self Assessment:

• 1 day late: £100 fine

• 3 months late: £10 per day (up to £900)

• 6 months late: further 5% of the tax due or £300, whichever is greater

For Corporation Tax:

• 1 day late: £100 fine

• 3 months late: another £100

• 6 months late: HMRC estimates your bill and adds a 10% surcharge

Beyond the financial impact, consistent late filing can raise red flags with HMRC, which may lead to additional scrutiny or compliance reviews.

Tips to Stay Ahead of Your Tax Deadlines

At Boobooks, we work closely with clients across the UK to simplify their tax process. Here are some professional tips from our accounting experts:

1. Keep digital records throughout the year
   Maintaining updated records saves time when tax season arrives. Use accounting software or cloud tools to track income, expenses, and receipts.
   

2. Set reminders early
   Add all key dates to your calendar, both personal and business, and set automated alerts at least a month in advance.
   

3. Review your tax position quarterly
   Don’t wait until the end of the year to calculate your liabilities. Reviewing quarterly can help manage cash flow and avoid surprises.
   

4. Work with a qualified accountant
   Partnering with a reliable accountant like Boobooks ensures your filings are accurate, compliant, and submitted on time. It also helps you optimize deductions and claim reliefs you might otherwise overlook.
   

5. Stay informed of HMRC updates
   Tax rules and thresholds can change yearly. Staying updated, or letting your accountant handle it, ensures you’re never caught off guard.
   

Why Choose Boobooks for Your Tax Filing

Tax filing doesn’t have to be stressful. At Boobooks, we take the complexity out of accounting so you can focus on running your business or managing your personal finances confidently.

Our experienced accountants handle everything from self-assessment tax returns to corporate tax compliance and financial planning. We’re not just number crunchers, we’re your strategic partners in financial success.

We ensure your UK tax returns are filed accurately, on time, and in full compliance with HMRC regulations. With Boobooks, you can trust that your accounts are in expert hands, leaving you free to focus on what matters most.

Final Thoughts

Understanding when tax returns are due in the UK is the first step toward a smoother, stress-free financial year. Whether you’re self-employed, running a limited company, or managing complex accounts, staying ahead of deadlines keeps your finances healthy and your record spotless.

With the UK tax returns deadline fast approaching, now is the best time to organize your paperwork and get expert help.

Contact Boobooks today for hassle-free tax filing, and let us help you stay compliant, confident, and in control.