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Start filing →The Self Assessment deadline is one of the most important dates in the UK tax calendar. Miss it and you face automatic penalties — even if you owe no tax. Here are all the dates you need to know for the 2024/25 tax year.
| Date | What happens |
|---|---|
| 5 April 2025 | 2024/25 tax year ends |
| 5 October 2025 | Deadline to register for Self Assessment (new filers) |
| 31 October 2025 | Paper return filing deadline |
| 30 December 2025 | Deadline to request HMRC collects tax via PAYE (if eligible) |
| 31 January 2026 | Online return filing deadline AND payment deadline |
| 31 July 2026 | Second payment on account deadline (if applicable) |
What Happens If You Miss the Deadline?
| How late | Penalty |
|---|---|
| 1 day late | Automatic £100 fine |
| 3 months late | £10/day for up to 90 days (£900 additional) |
| 6 months late | 5% of tax owed or £300 — whichever is greater |
| 12 months late | Further 5% or £300 penalty |
What Is a Payment on Account?
If your tax bill for the year is over £1,000 and less than 80% was collected through PAYE, HMRC requires you to make advance payments towards next year's bill. These are called payments on account:
- First payment on account: 31 January (with your annual bill)
- Second payment on account: 31 July
Each payment is 50% of the previous year's tax bill. First-time filers are often surprised by this — your January bill can be 150% of what you expected.
How to Make Sure You File on Time
Register by 5 October
If you've never filed before, register with HMRC first. They send your UTR by post — allow 10 working days.
Gather your records early
Collect P60s, self-employment income records, expense receipts, and rental income figures. Starting in November or December avoids January panic.
File with SubmitFox
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File before the deadline with SubmitFox
Start your return for free — you only pay when you're ready to submit.
Start your return for free. SubmitFox submits directly to HMRC — most people finish in under 20 minutes.
Common Questions
The online filing deadline for the 2024/25 tax year is 31 January 2026. This is also the payment deadline for any tax owed. The paper filing deadline is earlier: 31 October 2025.
HMRC occasionally extends the filing deadline in exceptional circumstances (as happened during COVID-19). However, you should never plan around an extension being granted. File on time or risk penalties.
If you registered for Self Assessment after 5 October, HMRC should allow you until 3 months from the date of registration to file, or 31 January, whichever is later. Check your HMRC online account for your specific deadline.
Possibly. If HMRC has asked you to file a Self Assessment return, you must file even if all your tax has been collected through PAYE. Not filing when required will still result in penalties.
5 April is the last day of the UK tax year. The 2024/25 tax year runs from 6 April 2024 to 5 April 2025. Any income earned up to 5 April 2025 must be declared in your 2024/25 return, due by 31 January 2026.