What are the Self-Assessment tax return deadlines?
There are several important Self-Assessment deadlines you need to be aware of for the 2024/25 tax year (which runs from 6 April 2024 to 5 April 2025):
Key deadlines for the 2024/25 tax year:
| Deadline | Date |
|---|---|
| Register for Self-Assessment (if new) | 5 October 2025 |
| Paper tax return deadline | 31 October 2025 |
| Online tax return deadline | 31 January 2026 |
| Pay the tax you owe | 31 January 2026 |
| Second payment on account | 31 July 2026 |
Why file online?
Filing online gives you an extra 3 months compared to filing on paper. The vast majority of people now file online. You also get an immediate calculation of the tax you owe.
Penalties for late filing:
- 1 day late: Immediate £100 penalty (even if you owe no tax or have paid the tax due)
- 3 months late: £10 per day for up to 90 days (maximum £900)
- 6 months late: The higher of £300 or 5% of the tax due
- 12 months late: The higher of £300 or 5% of the tax due (can be higher in serious cases)
Penalties for late payment:
- 30 days late: 5% of the tax unpaid at that date
- 6 months late: A further 5% of the tax still unpaid
- 12 months late: A further 5% of the tax still unpaid
Interest is also charged on late payments from the due date.
Top tip: File your return as early as possible after 6 April, even if you cannot pay immediately. Filing early does not mean you have to pay early. The payment deadline is still 31 January regardless of when you file. Filing early also gives you more time to budget for any tax bill.
No spam. Just this answer, straight to your inbox.