Deadlines
Six dates that followfrom one certificate.
Everything Companies House and HMRC expect from a new company is measured from the date of incorporation. Put it in and read them off.
Dates are worked out from the published rules on GOV.UK, checked 2026-09-04. Companies House can move an accounting reference date on application, and a first Corporation Tax period longer than twelve months splits into two returns.
The rules the calculator uses
No interpretation. These are the published rules with the page each one comes from.
| Filing | Who wants it | Deadline | Source |
|---|---|---|---|
| Incorporation IN01 | Companies House | Once, at the start | gov.uk |
| Confirmation statement CS01 | Companies House | Within 14 days of the end of each 12 month review period | gov.uk |
| Annual accounts AA | Companies House | 21 months after registration for the first set, then 9 months after each financial year end | gov.uk |
| Company Tax Return CT600 | HMRC | 12 months after the end of the accounting period | gov.uk |
| Corporation Tax payment CT PAY | HMRC | 9 months and 1 day after the end of the accounting period | gov.uk |
What late costs
Companies House penalties for a private limited company.
Up to 1 month late
£150
1 to 3 months late
£375
3 to 6 months late
£750
More than 6 months late
£1,500
Doubled if accounts are late two years running. Source: gov.uk/annual-accounts/penalties-for-late-filing