Self Assessment deadlines are non-negotiable. Missing them means penalties, interest, and potential enforcement action from HMRC. If you're self-employed, a company director, or have other income, understanding these dates is essential. Here's everything you need to know about Self Assessment deadlines for the 2024/25 tax year.
Key Self Assessment Deadlines for 2024/25
31 October 2024 – Deadline for Paper Returns
If filing a paper return (which is rare and not recommended), this is the deadline. Most people file online, so this date is largely obsolete. However, if you have special circumstances preventing online filing, you must request a paper form before this deadline.
31 January 2025 – The Main Deadline
This is the critical deadline. By 31 January 2025, you must:
- •File your Self Assessment tax return online
- •Pay any tax owing for the previous year (2023/24)
- •Make your first payment on account for the current year if applicable
For the 2024/25 tax year, this means filing by 31 January 2025 and paying tax owed for 2023/24, plus the first payment on account (typically 50% of your estimated tax for 2024/25).
31 July 2025 – Second Payment on Account
If you're required to make payments on account (typically if you owed more than £1,000 tax), your second payment is due by 31 July 2025. This is another 50% of your estimated tax for 2024/25.
Understanding Payments on Account
Payments on account are instalments of tax you're expected to pay during the tax year, rather than in one lump sum at the end. Here's how they work:
- •First payment (January): Due 31 January in the tax year, typically equal to 50% of your previous year's tax
- •Second payment (July): Due 31 July, also typically 50% of your previous year's tax
- •Final payment (January): Due 31 January the following year, balancing out any difference between payments on account and your actual tax liability
What You Need Before the Deadline
To file your return on time, gather these documents:
- •Total business income (from invoices or sales records)
- •All business expenses and allowable deductions
- •Employment income details (P60 or payslips)
- •Interest, dividend, and rental income records
- •Gift Aid donation receipts
- •Any other relevant income or deduction documents
Penalties for Missing Deadlines
HMRC penalties are serious and escalate quickly if you miss deadlines:
- •Late filing (up to 3 months late): £100 fixed penalty
- •3-6 months late: Additional penalty of 5% of tax owed or £300, whichever is higher
- •6-12 months late: Additional penalty of 5% of tax owed or £300, whichever is higher
- •Late payment of tax: Interest on unpaid tax plus potential penalties of 5%, 10%, or more depending on how late
How to File Your Return
HMRC requires all Self Assessment returns to be filed online through their Self Assessment portal:
- 1.Log in to your HMRC Self Assessment account at tax.service.gov.uk
- 2.Complete your tax return (either directly or import data from accounting software)
- 3.Review the calculations and check for accuracy
- 4.Submit the return (before 31 January)
- 5.Pay any tax due (also by 31 January or 31 July for payments on account)
Payment Methods
You can pay Self Assessment tax through several methods:
- •Online banking (fastest and safest option)
- •Debit or credit card (via the government payment service)
- •Cheque (payable to HMRC with payment slip)
- •Direct debit (set up Time to Pay arrangement)
Pro Tips for Meeting Your Deadlines
- •Start early: Don't wait until January. Gather records and prepare throughout the year
- •Use accounting software: Software can import data directly into your return, saving time and reducing errors
- •Set reminders: Mark the key dates (31 October, 31 January, 31 July) in your calendar with advance warnings
- •Keep records: Store all receipts, invoices, and documents for at least 6 years
- •Get professional help: Consider working with an accountant if Self Assessment is complex or stressful
Takeaway
Self Assessment deadlines are non-negotiable, and penalties for missing them are substantial. The key is to organize your records throughout the year, stay aware of deadlines, and file early if possible. Missing a deadline by even one day can result in a £100 penalty—easily avoided with basic planning.
If Self Assessment feels overwhelming, we can help. Our team prepares returns for self-employed individuals and company directors, ensuring everything is filed on time and you maximize your allowable deductions. Let's discuss how we can take the stress out of tax time.