How to Apply for a Companies House Filing Extension (Accounts Deadline)

Your accounts filing deadline is approaching and you won't make it. The good news: you can extend it. The bad news: you must act before the current deadline passes — late filing penalties are automatic and cannot be reversed just because you applied for an extension afterwards.

There are two routes to extend your deadline, and they work in very different situations.

Route 1: Apply for an Extension (Exceptional Circumstances)

You can apply to Companies House for more time to file your accounts if something outside your control prevents you from filing on time.

How to apply: Use the online extension application on Companies House.

What qualifies as exceptional circumstances:

• Serious illness of the director or key person responsible for accounts
• Fire, flood, or natural disaster that destroyed accounting records
• Bereavement of someone essential to the accounts preparation

What does NOT qualify:

• Your accountant was late or busy
• You forgot the deadline
• You didn't have the money to pay an accountant
• The company is dormant (filing dormant company accounts is still mandatory)
• You were abroad

Companies House will email you to say whether your application has been successful — and GOV.UK says to file by your deadline if possible rather than wait for a decision. If it's approved, Companies House sets a new deadline, but the law caps the total filing period at 12 months after the end of the accounting reference period, so a private company on the normal nine-month deadline can get at most three extra months.

Critical rule: You must apply before your filing deadline passes. An application submitted after the deadline will not prevent or reverse a late filing penalty.

Route 2: Change Your Accounting Reference Date

This is the more practical option for most directors. You can change your company's accounting reference date (ARD), which recalculates your filing deadline (unless you're lengthening the company's first financial year — see step 3).

How it works:

1. File a Change of Accounting Reference Date (AA01) form through Companies House WebFiling
2. Extend your current financial year so that it runs for no more than 18 months in total (for a normal 12-month year, that's up to 6 extra months)
3. Your new accounts filing deadline is normally 9 months after the new ARD — but GOV.UK says lengthening a company's first financial year doesn't change its deadline: first accounts covering more than 12 months are due 21 months after incorporation (or 3 months after the new ARD, if that's later)

Example (a company past its first accounts): Your ARD is 31 March 2026, giving you a filing deadline of 31 December 2026. You extend the ARD to 30 September 2026 — your new filing deadline becomes 30 June 2027.

Rules for extending your ARD:

• The extended period can't run for more than 18 months in total (s.392(5)). For a normal 12-month year that's up to 6 extra months, but don't simply add 6 months: a first period counts from the date of incorporation, and Companies House rejects an application that takes a period past 18 months
• You can't extend again within 5 years of the end of a period that was previously extended (exceptions in s.392(3): aligning with a UK parent or subsidiary undertaking's year end, a company in administration, or a direction from the Secretary of State)
• The extension must be filed before your current accounts deadline passes
• A shorter accounting period means shorter accounts — but you still file for the period covered

Shortening the ARD — the quicker alternative:

You can also shorten your financial year, which can be useful if your accounts are nearly ready but your deadline has already been set far in advance. Shortening the ARD by even one day recalculates the deadline as the later of:

• the normal deadline for the new (shortened) period: 9 months after the new ARD (for first accounts that still cover more than 12 months, 21 months after incorporation, or 3 months after the new ARD if later), or
• 3 months from the date Companies House receives the form

There's no limit on how often you can shorten your financial year.

Which Route Should You Choose?

Situation	Best route	Why
Genuine emergency (fire, illness, bereavement)	Extension application	Designed for unexpected events; preserves your normal accounting period
Running behind but no exceptional circumstances	ARD change	You don't need a qualifying reason; practical for most situations
First year of business, unsure of deadlines	Check the register first	Companies House shows your first accounts deadline online; GOV.UK says lengthening a company's first financial year doesn't change that deadline (first accounts are due 21 months after incorporation)
Accountant running late	ARD change	"My accountant was late" won't qualify for an extension
Already past the deadline	Neither	Late filing penalties are automatic; neither route can reverse a penalty that's already been triggered

What You Cannot Extend

Confirmation statement deadlines cannot be extended. The 14-day filing window after your review period ends is fixed. If you miss it, you're overdue — here's what happens if your confirmation statement is overdue and why there's no extension mechanism.

Identity verification deadlines during the transition period (November 2025 – November 2026) are tied to your next confirmation statement only if the person is a director; a PSC who is not a director has a fixed appointed day set by their birth month instead (S.I. 2025/1118 reg. 5). Extending your accounts deadline does not affect when you need to verify your identity. If you're not sure where your directors stand, check your identity verification readiness with our free assessment.

If you've missed a deadline and face penalties, see our complete guide to late filing penalties for the exact amounts and appeal options.

Avoid the Need for Extensions

The best extension is one you never need. If you file 2–3 weeks before your deadline, you have time to:

• Correct technical rejections, which routinely catch out filings made near deadlines
• Request your authentication code if you've lost it — Companies House posts a reminder of the existing code (up to 10 working days)
• Get professional help if your accounts aren't straightforward

Set reminders at 60, 30, and 14 days before each deadline. If you run multiple companies, each has its own ARD and filing deadline — a single missed one among several is easy when tracking dates manually. Use our free filing deadline countdown tool to estimate each company's accounts and confirmation statement deadlines and add them to your calendar, running it once for each company.

Sources

• Apply to extend your accounts filing deadline — Companies House
• Change your company accounting reference date (AA01) — GOV.UK