Self-Assessment Tax Return Deadlines & Penalties 2024/25
Complete guide to self-assessment deadlines for the 2024/25 tax year. Learn when to file, what penalties apply for late submission, and how to avoid them.
Key Dates for 2024/25 Tax Year
The 2024/25 tax year runs from 6 April 2024 to 5 April 2025. Here are the critical deadlines you need to know:
Registration Deadline
- 5 October 2025 - Register for self-assessment if you have not filed a return before
Filing Deadlines
- 31 October 2025 - Paper tax return deadline
- 31 January 2026 - Online tax return deadline
- 31 January 2026 - Payment deadline for tax owed
Late Filing Penalties
HMRC takes deadlines seriously. Here is what happens if you miss them:
| Time After Deadline | Penalty |
| 1 day late | £100 fixed penalty |
| 3 months late | £10 per day (up to 90 days = £900) |
| 6 months late | £300 or 5% of tax due (whichever is greater) |
| 12 months late | Additional £300 or 5% of tax due |
Total potential penalty for being 12 months late: £1,600 plus percentage penalties
Late Payment Penalties
If you owe tax and pay late:
- 30 days late - 5% of tax unpaid
- 6 months late - Additional 5%
- 12 months late - Additional 5%
Plus interest charged on all late payments from the due date.
Who Needs to File a Self-Assessment Return?
You must file if you:
- Are self-employed with income over £1,000
- Are a company director (unless only paid through PAYE with no other income)
- Have rental income
- Have capital gains to report
- Have foreign income
- Have income over £100,000
- Need to claim tax relief on pension contributions or charitable donations
- Are a higher rate taxpayer with savings income
How to Avoid Penalties
1. Start early - Do not leave it until January
2. Keep good records - Throughout the year, not just at tax time
3. Use an accountant - We handle deadlines for you
4. Set reminders - Calendar alerts for key dates
5. File even if you cannot pay - The filing penalty is separate from payment penalties
Need Help With Your Tax Return?
At Stoke Accounting Services, we prepare and submit self-assessment returns for individuals across Stoke-on-Trent and Staffordshire. Our personal tax service starts from £150 and includes:
- Full return preparation
- Expense review to maximise deductions
- On-time submission guaranteed
- HMRC correspondence handling
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