When Should I Submit My Self Assessment Tax Return?
We outline key deadlines, the benefits of early submission and expert tips to help you stay ahead of HMRC requirements
Self Assessment Tax Return Deadline
If you're required to complete a Self Assessment tax return, knowing when to submit it is crucial to avoid penalties and ensure your financial affairs are in order. Whether you're self-employed, a company director, or receiving untaxed income, early preparation can save stress and money.
Key Self Assessment Deadlines for the 2024/25 Tax Year
| Action | Deadline |
|---|---|
| Register for Self Assessment | 5 October 2025 |
| Paper Tax Return Submission | Midnight, 31 October 2025 |
| Online Tax Return Submission | Midnight, 31 January 2026 |
| Pay Tax Owed (and 1st Payment on Account) | Midnight, 31 January 2026 |
| 2nd Payment on Account | 31 July 2026 |
Can I Submit My Tax Return Early?
Yes — and it’s often a wise choice. HMRC allows you to file your return as soon as the tax year ends on 5 April. This means for the 2024/25 tax year, you can start submitting from 6 April 2025.
Benefits of early filing include:
✅ Better cash flow planning
✅ Avoiding last-minute stress
✅ Faster tax refund (if due)
✅ More time to seek help or correct errors
✅ Improved mortgage or loan application preparation (some lenders request up-to-date tax returns)
Common Reasons People Delay — and Why You Shouldn’t
Many taxpayers delay submission due to:
Lack of paperwork
Confusion over allowable expenses
Misunderstanding income sources that require reporting
Anxiety about making a mistake
However, delaying increases your risk of:
Late filing penalties (starting at £100)
Interest on unpaid tax
Being flagged for further HMRC scrutiny
Tip: Even if you can’t afford to pay your tax bill immediately, filing your return on time avoids penalties and opens the door to arranging a payment plan with HMRC.
Who Needs to File a Self Assessment Tax Return?
You’ll likely need to file if you:
Are self-employed or a sole trader
Are a company director (excluding PAYE-only directors)
Earn rental income from property
Receive foreign income
Earn over £100,000
Have untaxed income (e.g. investments, dividends)
Are claiming child benefit and earn over £50,000 (High-Income Child Benefit Charge)
Are a partner in a business partnership
How Early Filing Helps You Plan Better
Early filing doesn't mean early payment — your tax is still due by 31 January. However, knowing your liability early gives you:
Time to save or budget accordingly
The option to make voluntary payments towards your tax bill
Peace of mind if you're due a refund
What If You Miss the Deadline?
If you submit late:
You’ll receive a £100 fine immediately (even if no tax is due)
After 3 months, further daily penalties of £10 per day (up to £900) apply
After 6 months, an additional 5% of tax owed (or £300) is charged
Late payment also attracts interest and surcharges
Don’t ignore it. HMRC offers a “reasonable excuse” provision, but this only applies to serious, unforeseen issues — not disorganisation.
Real-World Example
Sophie, a freelance graphic designer, filed her 2024/25 return on 6 April 2025. By doing so:
She received her £1,200 refund by 20 April
Had 10 months to plan for her next payment on account
Used her return to secure a mortgage, with her accountant providing the SA302 form early
Expert Advice: Submit Early, Not Just On Time
Tax advisors, accountants, and even HMRC recommend filing as early as possible. Not only does it reduce the risk of penalties, but it also opens up opportunities for better tax planning and potentially reducing future liabilities.
Summary: Key Takeaways
- File early: You can submit from 6 April following the tax year end
- Deadline: 31 January for online returns and payment
- Plan ahead: Early submission means more time to save and correct
- Avoid fines: Late returns attract automatic penalties
- Seek support: Use a qualified accountant if unsure
Frequently Asked Questions (FAQs)
Q: Can I file my Self Assessment before I get all my income documents?
A: You should wait until all your income details are available to avoid submitting incorrect information. However, you can prepare everything in advance and file soon after receiving them.
Q: Do I need to pay when I file early?
A: No, you still have until 31 January to pay, even if you file your return earlier.
Q: Will I get my tax refund quicker if I submit early?
A: Yes. Refunds are usually processed within a few weeks of submission if HMRC owes you money.
Q: What happens if I submit a return late but owe no tax?
A: You’ll still be fined £100 for late filing — regardless of your tax liability.
Let Us Help You Get It Right
Our chartered accountants have years of experience supporting individuals, sole traders and small business owners through Self Assessment. Whether you're filing for the first time or managing multiple income streams, we’ll help you file correctly and on time — with no stress.
Contact us today for expert Self Assessment support.