UK Tax Diary August/September 2026
1 August 2026 – Due date for Corporation Tax due for the year ended 31 October 2025.
7 August 2026 – Making Tax Digital (MTD) for Income Tax first quarterly update deadline for self-employed individuals and landlords mandated to comply with MTD. This quarterly update covers the period 6 April 2026 to 5 July 2026.
7 August 2026 – VAT Return and Payment Deadline for businesses submitting quarterly VAT Returns with a VAT period ending 30 June 2026. Returns must be submitted and any VAT due paid electronically by this date.
19 August 2026 – PAYE and NIC deductions due for the month ended 5 August 2026. (If you pay electronically, the due date is 22 August 2026.)
19 August 2026 – Filing deadline for the CIS300 monthly return for the month ended 5 August 2026.
19 August 2026 – CIS tax deducted for the month ended 5 August 2026 is payable by today.
1 September 2026 – Due date for Corporation Tax due for the year ended 30 November 2025.
19 September 2026 – PAYE and NIC deductions due for the month ended 5 September 2026. (If you pay electronically, the due date is 22 September 2026.)
19 September 2026 – Filing deadline for the CIS300 monthly return for the month ended 5 September 2026.
19 September 2026 – CIS tax deducted for the month ended 5 September 2026 is payable by today.
