Don’t Miss Your Self-Assessment Deadlines: What You Need to Know for Smooth Tax Filing
If you’re self-employed, a landlord, or have additional untaxed income, self-assessment is a key part of your financial calendar. Missing deadlines can lead to unnecessary penalties and stress, but with the right approach, staying on top of your tax can be straightforward.
Here’s what you need to know for the 2025 tax year, plus practical tips to stay in control.
Key Self-Assessment Deadlines
✅ 5 October 2025 – Register for self-assessment if you’re newly self-employed or have untaxed income.
✅ 31 October 2025 – Paper tax return filing deadline (only applicable if filing by post).
✅ 31 January 2026 – Online tax return filing deadline and payment of tax due for the 2024/25 tax year.
✅ 31 July 2026 – Second payment on account due, if applicable.
Missing these deadlines results in:
A £100 automatic fine if you miss the 31 January deadline.
Further penalties and interest if your payment is late.
Tips to Stay on Top of Self-Assessment
1. Keep Records Updated Throughout the Year
Track your income and expenses monthly. This will save you from scrambling in January and help you claim all eligible expenses, reducing your tax bill.
2. Use Accounting Software
Consider using cloud-based software like Xero, QuickBooks, or FreeAgent to categorise transactions automatically and store receipts digitally.
3. Set Calendar Reminders
Block out key dates in your phone or calendar and set reminders a few weeks before each deadline.
4. File Early
You don’t have to wait until January to file your return. Filing early:
Gives you peace of mind.
Allows time to budget for any tax owed.
Helps you get your tax refund faster if you are due one.
5. Speak to Your Accountant
Your accountant can help you plan your tax liability, ensure all deductions are claimed, and advise on payments on account.
Understanding Payments on Account
If your last self-assessment tax bill was over £1,000, you may need to make payments on account.
What are they?
Payments on account are advance payments towards your next year’s tax bill, made in two instalments:
31 January
31 July
Each payment is typically 50% of your previous year’s tax bill, excluding student loan repayments and Capital Gains Tax.
For example:
If your 2024/25 tax bill is £4,000:
You pay £4,000 by 31 January 2026.
You pay £2,000 (50%) on 31 January 2026 (first payment on account for 2025/26).
You pay £2,000 (50%) on 31 July 2026 (second payment on account for 2025/26).
When you file your 2025/26 return, your payments on account will be deducted from your final tax bill. If your income drops, you can apply to reduce your payments on account.
How We Can Help
At NF Accounting, we can:
✅ Register you for self-assessment if you’re newly self-employed.
✅ Prepare and file your tax return accurately and efficiently.
✅ Advise on allowable expenses and reliefs to reduce your tax bill.
✅ Help you manage payments on account and apply for reductions if your income is lower.
✅ Provide reminders and structured tax planning to avoid last-minute stress.
Ready to take the stress out of your tax return?
Contact us today to discuss your self-assessment needs and stay ahead of your tax deadlines with confidence.