Tax20 October 20266 min read

Companies House Deadlines: What You Owe, When, and What Happens If You Are Late

Four deadlines come from one date, owed to two organisations. Which two to look up rather than calculate, and why your tax is due before your return.

One date, four deadlines, two organisations

If your business is a limited company, almost every filing deadline you have hangs off one date: the end of your accounting period, usually called your year end. Four obligations come out of it, spread across the year that follows, and they are owed to two different organisations.

Companies House wants your annual accounts, and separately a confirmation statement. HMRC wants the corporation tax paid, and then the company tax return filed. Filing your accounts does not pay your tax, and paying your tax does not file anything.

Two of those four dates are published for you. Two you work out yourself, and the arithmetic is where people come unstuck.

Your accounts deadline is a date, not a rule

Companies House states the date your next accounts are due, for your company specifically, on the public register. It is a stated fact about your company, not a calculation you perform.

That matters more than it sounds. The rule of thumb, nine months after your year end, is right for most companies in most years and wrong often enough to be dangerous: a first set of accounts, a shortened or extended period, or a year end you changed can all land you somewhere else.

So look it up instead of counting months. Search the Companies House register for your own company and read the date off your own record. It takes a moment, and it is the authority.

The confirmation statement is not your accounts

The confirmation statement catches more first-time directors than anything else here, because it sounds like an accounting document and is not one. It contains no figures. It confirms who owns the company, who runs it, where it is registered and what it does, and asks you to say that is still correct.

It has its own due date, also on your own record, and that date has nothing to do with your year end. You can be perfectly up to date on accounts and overdue on your confirmation statement, and plenty of companies are.

Corporation tax: you pay before you file

Here are the two dates nobody publishes for you.

Corporation tax is payable nine months and one day after the end of your accounting period. The company tax return is due twelve months after it. The order is the whole point: the money is due roughly three months before the return that works out how much it was.

So you cannot wait for your accountant to finish the accounts before paying. Add the day first, then the nine months, or you will be a day out on some year ends:

Year end 31 December 2025: pay by 1 October 2026, file by 31 December 2026
Year end 31 March 2026: pay by 1 January 2027, file by 31 March 2027
Year end 30 June 2026: pay by 1 April 2027, file by 30 June 2027

That last one is the warning. Nine months on from 30 June is 30 March, and a day after that is 31 March, which is wrong. Add the day first and you get 1 July, and nine months on from there is 1 April. A day out on a tax payment is still late.

Two assumptions sit behind this, true for most small companies and not all: that you have one tax accounting period matching your accounts, which a first year longer than twelve months does not, and that you do not pay in quarterly instalments, which broadly applies above 1.5 million pounds of profit. If either is in doubt, ask your accountant.

What actually happens when you are late

Your lateness is published. This is the consequence owners underrate, and the register holds more than your due dates. It also holds a plain yes or no on whether you are overdue, and anyone can look it up. A prospective customer running a check, a lender, or a supplier setting your credit terms sees it without having to ask you.

Companies House charges a late filing penalty for accounts, on a scale it publishes itself, which rises the later you are. We will not quote figures from memory, which is exactly the sort of number that goes stale in a blog post: read the scale on the Companies House site, where it is correct by definition.

Late corporation tax accrues interest from the payment date, not the filing date. The same point as the section above, arriving as a cost.

What to do about it

Put your year end in the calendar once, then set four reminders after it rather than one. Read the two Companies House dates off the register, work the two tax dates forward with the day added first, and save the tax money against the payment date rather than the filing date.

How CFO Pal shows them

Link your company number in Settings and the Deadlines tab carries a Filing deadlines card: your accounts and confirmation statement dates exactly as Companies House states them, refreshed weekly, plus the two corporation tax dates derived from your accounting period. The derived ones are labelled as derived and say to confirm them with your accountant. Anything close to its deadline is flagged as due soon, and where Companies House itself says you are overdue, the card reports that in its own words rather than ours.

It shows you the dates. It does not file anything, and it is not a substitute for your accountant's own calendar.