Due
December 31, 2027
Corporate tax
Worked out for calendar quarters and a 31 December year end. General information, not advice for your company. Check your own dates with us before you rely on them.
Released by
HM Revenue and Customs (HMRC)
Period
Accounting period 1 January to 31 December 2026
Send records by
June 30, 2027
Last checked
October 20, 2026
What it is
Your Company Tax Return (CT600) for 2026, due 12 months after the period ends. The tax itself is due sooner: nine months and one day after the year end, so 1 October 2027.
What is new
- Fixed late filing penalties doubled for returns due on or after 1 April 2026: £200 if late, £400 if more than three months late.
- A third late return in a row now costs £1,000, or £2,000 if more than three months late.
Who it applies to
UK companies with an accounting period ending 31 December 2026.
What we do
- Prepare the tax computation from your final accounts.
- Claim capital allowances and research and development relief where they apply.
- Tell you the tax due and the 1 October payment date early.
- File the CT600 with tagged accounts and computations.
What we need from you
- Your final signed accounts.
- Fixed asset additions and disposals.
- Details of any research and development projects.
- Group and associated company details.
If it is late
£200 if late, £400 if more than three months late, then 10% of any unpaid tax at six months and again at twelve. Interest runs on tax paid after 1 October 2027.