Tax diary: October and November 2026

Autumn brings a busy run of deadlines. Therefore, we have set out the key dates below. Use this tax diary: October and November 2026 to plan ahead and avoid penalties.

Missing a deadline can trigger interest and surcharges. Consequently, diarising these dates early saves money and stress.

October 2026 deadlines

• 1 October 2026 – Corporation Tax payment falls due for companies with an accounting period ending 31 December 2025. However, this excludes companies making quarterly instalment payments.
• 5 October 2026 – Notify HMRC of any new liability to Income Tax or Capital Gains Tax for 2025–26. You may need to register for Self Assessment. For example, you became self-employed, started receiving taxable rental income, or received other untaxed income or gains.
• 7 October 2026 – VAT returns and payments are normally due for accounting periods ending 31 August 2026. Different deadlines sometimes apply. Additionally, Direct Debit payers should allow time for HMRC to collect.
• 19 October 2026 – PAYE, employee and employer National Insurance contributions, student loan deductions and Construction Industry Scheme deductions fall due. This covers the month ended 5 October 2026 where you pay by post.
• 19 October 2026 – Submit the CIS300 monthly return for the month ended 5 October 2026.
• 22 October 2026 – Make electronic payments of PAYE, National Insurance contributions, student loan deductions and CIS deductions for the month ended 5 October 2026.
• 22 October 2026 – Pay tax and Class 1B National Insurance contributions under a PAYE Settlement Agreement for 2025–26 electronically. Otherwise, the deadline is 19 October 2026.
• 31 October 2026 – File a paper Self Assessment tax return for the year ended 5 April 2026. Alternatively, you can normally file online by 31 January 2027.
• 31 October 2026 – Corporation Tax returns fall due for companies with an accounting period ending 31 October 2025.
• 31 October 2026 – Companies House accounts fall due for private companies with an accounting period ending 31 January 2026. Note that different deadlines apply to first accounts.
• 31 October 2026 – Plastic Packaging Tax returns and payments fall due for the quarter ended 30 September 2026, where registered.

November 2026 deadlines

• 1 November 2026 – Corporation Tax payment falls due for companies with an accounting period ending 31 January 2026. Again, this excludes quarterly instalment payers.
• 7 November 2026 – VAT returns and payments are normally due for accounting periods ending 30 September 2026. Meanwhile, Direct Debit payers should allow collection time.
• 19 November 2026 – PAYE, National Insurance contributions, student loan deductions and CIS deductions fall due for the month ended 5 November 2026 if you pay by post.
• 19 November 2026 – Submit the CIS300 monthly return for the month ended 5 November 2026.
• 22 November 2026 – Make electronic payments of PAYE, National Insurance contributions, student loan deductions and CIS deductions for the month ended 5 November 2026. Importantly, this date falls on a Sunday. Therefore, arrange payment early so cleared funds reach HMRC in time.
• 30 November 2026 – Corporation Tax returns fall due for companies with an accounting period ending 30 November 2025.
• 30 November 2026 – Companies House accounts fall due for private companies with an accounting period ending 28 February 2026. Once again, different deadlines apply to first accounts.

How to stay on track

First, check which dates actually apply to your business. Next, add them to your calendar with a reminder. Finally, allow extra days for weekend and bank holiday clearing times.

Talk to us about your deadlines

Keep this tax diary: October and November 2026 somewhere handy. Meanwhile, please contact us if you need help with returns, payments or registrations. We will make sure you meet every deadline with confidence.