The 2025/26 tax year runs from 6 April 2025 to 5 April 2026. If you need to file a self-assessment tax return for this period, you'll need to meet the deadlines in late 2026 and early 2027. Here's everything you need to know to stay compliant and avoid penalties.
Key Dates for 2025/26 Tax Year
- 6 April 2025– Start of 2025/26 tax year
- 5 April 2026– End of 2025/26 tax year
- 31 October 2026– Paper tax return deadline
- 31 January 2027– Online tax return deadline & payment due
💡 Plan Ahead
While the deadlines may seem far away, starting early gives you time to gather documents, claim all eligible expenses, and avoid last-minute stress. Many taxpayers file in April or May to get it out of the way.
Who Needs to File a Self-Assessment?
You must file a self-assessment tax return if you:
- Are self-employed as a sole trader with income over £1,000
- Are a partner in a business partnership
- Earn over £100,000 per year from any source
- Have income from property or land
- Have foreign income that needs declaring
- Receive dividends from shares or investments
- Need to claim tax relief on pension contributions
- Have capital gains that exceed the annual exempt amount
Penalties for Missing the Deadline
HMRC takes deadlines seriously. Here's what you'll face if you file late:
- 1 day late: £100 initial penalty (even if you owe no tax)
- 3 months late: Additional £10 per day (up to 90 days, max £900)
- 6 months late: Further £300 or 5% of tax due (whichever is higher)
- 12 months late: Another £300 or 5% of tax due
In serious cases, HMRC may charge up to 100% of the tax due for deliberate non-compliance.
What's New for 2025/26?
Keep these changes in mind when preparing your return:
- Making Tax Digital (MTD): MTD for Income Tax is being phased in for self-employed individuals and landlords with income over £50,000 from April 2026
- Dividend Allowance: The tax-free dividend allowance remains at £500
- Capital Gains Tax: The annual exempt amount remains at £3,000
- National Insurance: Check for any changes to NI thresholds and rates
Tips for Filing on Time
- Gather your documents early: P60, P11D, bank statements, invoices, and receipts
- Register for HMRC online services: If you haven't already, allow time for activation codes
- Use accounting software: Tools like Xero, QuickBooks, or FreeAgent can streamline the process
- Consider professional help: An accountant can ensure accuracy and identify tax-saving opportunities
- Set aside money for tax: Budget 25-30% of profits for your tax bill
- File early: You can submit from 6 April 2026 – filing early doesn't mean paying early
Need Help with Your Tax Return?
At FFC Accountants, we specialise in helping individuals and businesses meet their tax obligations. Whether you need help with a straightforward return or have complex income sources, our experienced team can prepare and submit your self-assessment quickly and accurately.
