Dormant company deadline calculator

How dormant company deadlines work

Every UK limited company — dormant or trading — has three recurring statutory deadlines. Miss any of them and the consequences range from automatic penalties to compulsory strike-off.

1. Annual accounts (Companies House)

Due 9 months after the end of your accounting reference period. First-year accounts work differently: with a default first period (longer than 12 months) they are due 21 months from incorporation — slightly earlier than the 9-month rule would suggest. See our full guide on dormant company filing deadlines for the mechanics.

2. Company tax return (HMRC)

Due 12 months after the end of your accounting period — three months later than your accounts. A CT600 is only due when HMRC sends a notice to deliver one; see do I need a CT600 for a dormant company.

3. Confirmation statement (CS01)

Due every 12 months: the review period runs from incorporation (or from your last confirmation statement) and ends the day before the anniversary, and you have 14 days after that to file. This is separate from accounts and has its own £50 filing fee. There is no automatic penalty for a late one, but not filing it is an offence: after a warning notice giving 28 days to file, Companies House can fine the company or its officers — £250 to £2,000 a penalty — and can start striking the company off.

Can my deadlines change?

Yes — you can shorten or extend your accounting reference period by filing an AA01 with Companies House. There are strict rules about how often and by how much. Most dormant companies leave their dates alone.

Where these dates come from

Look your company up by number and the accounts and confirmation statement dates are the ones on your Companies House record. A shortened accounting period, an early confirmation statement or a granted extension is already reflected in them — and a filing you are behind on is shown as overdue, rather than rolled forward to next year.

Enter an incorporation date by hand instead and the dates are a projection from the standard rules, which cannot know about any of that. The CT600 date is always a projection: HMRC sets your Corporation Tax periods with you directly, so if their letter gives different dates, follow the letter.