UK Tax Deadlines and Penalties to Watch in 2025
Staying on top of your tax obligations is essential to avoid unnecessary fines, interest charges, and stress. The UK tax system imposes strict deadlines for individuals, sole traders, landlords, and limited companies—and penalties for missing them can be costly.
This guide outlines the key UK tax deadlines and penalties to watch in 2025, helping you stay organised and compliant.
Key UK Tax Deadlines for 2025
Self-Assessment Deadlines
| Deadline | Requirement | Notes |
|---|---|---|
| 31 Jan 2025 | Online tax return for 2023/24 | Final deadline for online submission |
| 31 Jan 2025 | Payment of tax due for 2023/24 | Balancing payment + first payment on account for 2024/25 |
| 5 April 2025 | End of 2024/25 tax year | Useful for planning tax reliefs |
| 31 July 2025 | Second payment on account for 2024/25 | Applies to those with tax bills over £1,000 |
| 5 Oct 2025 | Register for self-assessment (2024/25) | For new self-employed individuals or landlords |
| 31 Oct 2025 | Paper tax return for 2024/25 | Earlier deadline than online |
| 31 Jan 2026 | Online return and payment for 2024/25 | Deadline for most taxpayers |
VAT Deadlines (Quarterly)
- Submit VAT returns one month and seven days after the end of each quarter
- Payment due at the same time
- Making Tax Digital (MTD) rules apply to all VAT-registered businesses
Corporation Tax Deadlines
- Filing deadline: 12 months after accounting period ends
- Payment deadline: 9 months and 1 day after period ends (for companies with taxable profits under £1.5 million)
PAYE and CIS Deadlines
- RTI (Real Time Information): Must be submitted on or before payday
- PAYE payment deadline: 22nd of each month (if paying electronically)
- CIS returns: Due by the 19th of the following month
Penalties for Missing Tax Deadlines
Self-Assessment Penalties
| Delay | Penalty |
| 1 day late | £100 fixed penalty |
| 3 months late | £10 per day (up to 90 days = £900) |
| 6 months late | Additional £300 or 5% of tax due (whichever is higher) |
| 12 months late | Additional £300 or up to 100% of tax due |
Late Payment Penalties
- 30 days: 5% of unpaid tax
- 6 months: additional 5%
- 12 months: another 5%
- Interest also accrues daily on unpaid amounts
VAT Penalties (Under New Regime)
- Points-based system for late returns:
- 1 point per late submission
- Penalties apply once threshold reached (e.g. 4 points for quarterly filers)
- Late payment penalties:
- 2% of unpaid VAT after 15 days
- Additional 2% after 30 days
- Daily interest thereafter
Corporation Tax Penalties
- 1 day late: £100
- 3 months late: Additional £100
- 6+ months: 10% of unpaid tax (plus interest)
- 12 months late: Further 10%
Tips to Stay Compliant
- Use accounting software to track deadlines
- Set calendar reminders and automate payments where possible
- File early and avoid last-minute rush
- Hire an accountant to ensure accurate and timely submissions
How Eclat Accountancy Can Help
At Eclat Accountancy, we:
- Monitor all your tax deadlines
- File returns and reports on your behalf
- Advise on payment plans and penalty avoidance
- Keep you compliant with HMRC and MTD rules
Final Thoughts
Missing tax deadlines can be expensive and stressful. With so many dates to track across different taxes, working with a proactive accountant can save you time and money.
Get in touch with Eclat Accountancy today to stay ahead of your 2025 tax responsibilities.
