Extending your accounts filing deadline: how to apply, what qualifies, and the two alternatives

The one rule that decides everything

An extension must be applied for BEFORE your filing deadline passes. Companies House's own guidance says it in one sentence: you must apply for the extension, or file your accounts, before your filing deadline, or you will receive a late filing penalty. After the deadline there is no extension, no discretion and no negotiation — the penalty exists from the first day and the only question left is which band you land in. If you are reading this with days in hand and a genuine problem, apply today; the application takes minutes and you should not wait for the decision before trying to file anyway.

Extension, year-end change or file late — which lever is yours?

Three different things get called 'extending the deadline', and they have different tests, different effects and different side effects. The table is the decision; the rest of this page is the extension column, and the year-end change has its own guide.

One interaction is worth knowing before you combine them: if you have an extension and then change the accounting reference date for the same period, the extension no longer applies — and if the new deadline has already passed when the change is made, the company gets an automatic penalty. Pick one lever.

What counts as an exceptional reason

Companies House grants extensions for events outside your control that stop the accounts being finished. Its published examples are an unexpected illness and a fire that destroyed the company's records a few days before the deadline. The late-filing guidance adds the mirror image — reasons that will NOT succeed on their own: the company is dormant, you cannot afford to pay, your accountant let you down, you did not know the deadline, the accounts were delayed in the post. The bar is 'exceptional', and the same bar applies to an appeal after the event, so a reason that would not win an appeal will not win an extension.

1. Likely to qualify: serious illness or bereavement of the person preparing the accounts; fire, flood or theft that took the records; an unforeseen event of that weight, close to the deadline.
2. Unlikely to qualify: workload, a busy or absent accountant, software problems, a change of accountant, 'the company is dormant and the accounts are a formality', not knowing the date.
3. Evidence helps and is optional: a doctor's letter, an insurer's or fire service reference, anything dated that shows the event and when it happened.

How to apply, step by step

The application is the online service 'Apply to extend your accounts filing deadline' on GOV.UK. It asks for three things and takes a few minutes; nothing is posted.

1. Have your company number ready (it is on every Companies House letter and on the public register).
2. Write the reason in plain English: what happened, when, and why it stops the accounts being filed by the deadline. Dates matter more than adjectives.
3. Attach any supporting document you have — optional, but a dated document is the difference between an assertion and evidence.
4. Submit. Companies House reviews the request and tells you the decision by email; it may email first if it needs more information.
5. Do not stop preparing the accounts while you wait. Companies House says plainly: it is important to file by the deadline if you can, and you should not wait for a decision.
6. If the extension is granted, file before the NEW date — missing an extended deadline earns the penalty like any other. If you meanwhile receive a letter chasing the accounts, that is the automatic reminder cycle, not a refusal.

A granted extension changes this year's deadline only. Your future accounts deadlines stay exactly where they were.

How long an extension can be

The law allows a maximum filing period of 12 months from the end of the financial year, counting the normal 9 months a private company already has. In practice that caps most extensions at three months, and a company that has already had one extension for the period may not be eligible for another. Companies House decides the length; the application asks why you need more time, not how much you want.

A worked example

A private company with a 31 March year end has its normal accounts deadline on 31 December. On 20 December the sole director is admitted to hospital. Applying on 21 December, with the admission date, is an application made before the deadline for an event outside the director's control — the shape Companies House describes. If it is granted to, say, 28 February, the accounts filed on 27 February carry no late filing penalty. The same accounts filed on 27 February with no extension would carry £375 (more than one month late); filed on 2 January with no extension, £150. The following year's deadline is still 31 December.

If the deadline already passed

Skip the extension page entirely — it cannot help now, and Companies House does not accept applications after the date. File the accounts as fast as they can honestly be prepared, because the penalty bands run on elapsed time: £150 becomes £375 at one month late, £750 at three and £1,500 at six, and the whole table doubles if last year's accounts were late too. For a dormant company the accounts are a page; being late by less is the only optimisation left. The accounts-overdue guide walks through what happens next, week by week.

Official sources

• Companies House guidance — Applying for more time to file your company's accounts
• Companies House guidance — Late filing penalties (bands, doubling, appeals)
• Companies House — Life of a company, part 1: accounts (deadlines and the ARD interaction)
• GOV.UK — Change your company's year end

Sources checked 1 November 2026.