06/01/2026
Welcome back after the festive season.
And we are here to help you.
your AI-powered guide to key HMRC deadlines
Staying on top of HMRC deadlines is simpler and more reliable than ever. Here are the key dates you need to know for the upcoming tax periods.
Self Assessment Tax Return Deadlines
The main deadlines for the 2024/25 tax year (which ended on 5 April 2025) are:
* 31 January 2026: Deadline for submitting your online tax return and paying any remaining tax you owe, plus your first payment on account for the 2025/26 tax year.
* 30 December 2025: Deadline to file your online return if you want HMRC to collect any underpayment (up to £3,000) automatically through your 2026/27 PAYE tax code.
* 31 July 2026: Deadline for your second payment on account for the 2025/26 tax year.
Corporation Tax Deadlines
Corporation Tax deadlines are linked to your company's specific accounting period end date.
* Payment Deadline: Corporation Tax is due 9 months and 1 day after the end of your accounting period.
* Filing Deadline: Your Company Tax Return (CT600) must be filed within 12 months of the end of your accounting period.
For example, for a company with a year-end of 31 March 2025, the payment was due by 1 January 2026, and the return must be filed by 31 March 2026.