Filing your Self-Assessment tax return on time is crucial to avoid escalating penalties and interest charges. At Friendly Assist Accountancy, we understand the complexities of the UK tax system and are here to help you navigate it effectively.
Key Deadlines
- Paper Tax Return must be received by HMRC by 31 October 2025
- Online Tax Return must be submitted by 31 January 2026
- Tax Payment is due by 31 January 2026
- Payment on Account second payment due by 31 July 2025
Note: If you register for Self-Assessment after 5 October 2025, your filing deadline will be three months from the date HMRC notifies you. (gov.uk)
Penalties for Late Filing
Missing the filing deadline can result in fines. The table below summarises how penalties are applied:
| Delay Period | Penalty |
|---|---|
| Up to 1 day after deadline | 100 pounds |
| 1 day to 3 months | 10 pounds per day (up to 900 pounds) |
| 3 to 6 months | 300 pounds or 5% of tax due, whichever is higher |
| 6 to 12 months | 300 pounds or 5% of tax due, whichever is higher |
| More than 12 months | Additional 300 pounds or 5% of tax due, plus interest |
These penalties apply even if no tax is due. (gov.uk)
Penalties for Late Payment
If you do not pay your tax on time, HMRC will charge:
| Delay Period | Penalty |
|---|---|
| 30 days | 5% of unpaid tax |
| 6 months | Additional 5% of unpaid tax |
| 12 months | Additional 5% of unpaid tax |
Interest is also charged on any unpaid amounts. (litrg.org.uk)
Common Mistakes to Avoid
- Missing deadlines: Ensure you are aware of all relevant dates to avoid penalties
- Incorrect information: Double-check your return for accuracy to prevent errors that could lead to fines
- Not registering on time: If you are new to Self-Assessment, register with HMRC by 5 October to avoid late registration penalties (gov.uk)
How Friendly Assist Accountancy Can Help
At Friendly Assist Accountancy, we offer:
- Self-Assessment filing from start to finish
- Tax planning to minimise your tax liability
- Penalty advice to avoid or appeal fines
- Specialist support for crypto investors, gig workers, and creators
Our services start from 89 pounds per year. (friendlyassistaccountancy.co.uk)
Recent Changes to Penalty Rates
As of April 2025, HMRC has increased interest rates on late payments to 8.25 percent, linked to the Bank of England base rate plus 4 percent. (outbooks.co.uk)
Contact Us
Do not risk unnecessary penalties. Contact Friendly Assist Accountancy today to ensure your Self-Assessment is filed correctly and on time.
References
- HMRC Self-Assessment Penalties: gov.uk
- HMRC Self-Assessment Deadlines: gov.uk
- LITRG Tax Penalties and Interest: litrg.org.uk