Every UK limited company must prepare and file annual accounts with Companies House and HMRC each year. Miss the deadline – even by a single day – and you’ll face an automatic late filing penalty.
Deadlines don’t always go to plan. Maybe your accountant is behind schedule, you’ve had a challenging year, or you simply need a bit more breathing space. The good news is that there are legitimate ways to get more time.
This guide explains the two main options for extending your company accounts deadline, how they work, and what to watch out for.
Key takeaways
- You can extend your accounts filing deadline by changing your accounting reference date (ARD) or requesting an extension from Companies House due to exceptional circumstances.
- Changing your ARD affects your Corporation Tax filing deadlines with HMRC, so speak to your accountant before making any changes.
- Late filing penalties start at £150 and double if you file late two years running – so act before your deadline passes, not after.
Understanding your accounting reference date (ARD)
Your Companies House filing deadline for annual accounts is calculated from a single date: your accounting reference date, or ARD.
Your ARD is the date your company’s financial year ends. It’s set automatically when you register your company and falls on the last day of the month in which your incorporation anniversary falls.
- Company filing and reporting requirements
- Dormant company accounts explained
- Late filing penalties for limited companies
For example, if your company was incorporated on 15 March 2025, your ARD would therefore be 31 March 2026. Your first financial year would run from the date of incorporation until 31 March 2026, and every financial year after that would run from 1 April to 31 March.
You must file your annual accounts within:
- 21 months of the date of incorporation for your first accounts
- 9 months of your ARD for every year after that
These deadlines apply to every UK limited company, whether it’s actively trading or dormant.
Move the ARD, and your deadlines will generally move with it. This is why changing your ARD can enable you to extend your accounts filing deadline.
Two ways to extend your accounts filing deadline
There are two routes available to you if you need more time to file your company accounts with Companies House.
- Option 1 – Apply for a deadline extension – if something unexpected happens – a fire, flood, theft, or serious illness – you can ask Companies House to grant you extra time. This is a formal application and must be submitted before your current deadline.
- Option 2 – Change your ARD – by adjusting the date your company’s financial year ends, you can often move your filing deadline. You can do this yourself using form AA01 online or by post.
For option 2, there are a few important conditions. You can only change the ARD for your current financial year or the one immediately before it, and you can’t change your accounting reference date if your company accounts are already overdue. If you submit the change in time but your new recalculated filing deadline has already passed, your accounts will still be treated as late, and a late filing penalty will apply.
The extension is different altogether, as it doesn’t change your accounting year at all. It’s a deadline extension designed for genuine emergencies and carries stricter criteria.
Why changing your ARD affects your filing deadline
When you change your accounting reference date using form AA01, Companies House recalculates your filing deadline. How this affects you depends on whether you shorten or extend your financial year.
If you shorten your financial year, your new deadline becomes the later of:
- Nine months from the new accounting reference date
- Three months from the date Companies House receives your form
This is the mechanism that can give you extra time to file. Even a slight adjustment to your year-end (e.g. a day) can extend your deadline by several weeks or months.
If you extend your financial year instead, unless it’s your company’s first set of accounts, your filing deadline usually moves in line with the new year-end. This gives you more time overall, but it also means your accounts will cover a longer period.
How to shorten your company’s financial year
You can shorten your financial year by any number of days, weeks, or months within the current financial year or the immediately previous one.
Companies shorten their financial year for a range of legitimate business reasons, including:
- Aligning their year-end with a parent or subsidiary
- Matching their accounts to seasonal trading patterns
- Preparing for restructuring, investment, or new ownership
- Moving their year-end to a quieter period for accounting and audit work
- Simplifying internal reporting and planning
However, some companies may use this rule to change their filing deadline without making a formal request for a deadline extension. It’s not generally recommended, although companies do sometimes make use of it.
Under the current rules, you can do this as often as you like. This was set to be restricted to once every five years from April 2027 under the Economic Crime and Corporate Transparency Act (ECCTA), but the change has since been paused pending a final decision. Had the reforms gone ahead, you would only have been able to shorten your ARD once every five years unless you could demonstrate a ‘valid business reason’.
What happens when you shorten your financial year: An example
Suppose your company’s current ARD is 31 March 2026, so your accounts would typically be due by 31 December 2026. On 1 November 2026, you submit form AA01 to shorten your financial year by one day, moving your accounting reference date to 30 March 2026.
Assuming Companies House receives and processes your application on the same day, your new filing deadline is then calculated as the later of:
- Nine months after the new ARD – 30 December 2026
- Three months from the date the form is received – 1 February 2027
In this case, the later date is 1 February 2027. By shortening your financial year by just one day and submitting the form close to your original deadline, you have moved your filing deadline from 31 December 2026 to 1 February 2027, gaining an extra month without applying for a formal extension.
How to extend your company’s financial year
You can extend your financial year for up to 18 months, but you can only do so once every five years. However, there are exceptions, for example if:
- Your company is in administration
- You are aligning your ARD with a parent company or subsidiary registered in the UK or European Economic Area
- You have approval from Companies House
- You are filing on behalf of an overseas company
Lengthening your financial year extends the period your accounts need to cover, but it also pushes your filing deadline into the future, giving you more time to prepare.
The rules were due to change from April 2027, but have been paused
Under the ECCTA, Companies House had planned to restrict how often companies can shorten their accounting period. From April 2027, you would only have been able to shorten your ARD once every five years, unless you could provide a valid business reason.
However, following stakeholder concerns, these reforms have been put on hold and are currently under review. Companies House has confirmed they will not be introduced in April 2027, and businesses will be given at least 21 months’ notice before any new rules take effect.
For now, you can still shorten your ARD as many times as you like – meaning the tactic of shortening your ARD to gain three extra months of filing time remains available without restriction.
That said, this is a pause, not a cancellation. If the reforms are reintroduced, the once-every-five-years limit would mean this tactic could only work once before you’d need to wait five years – unless Companies House accepted your reason for the change.
The exact criteria for what would qualify as a “valid business reason” was never published. However, we can look at the existing rules on extending your ARD (which have been limited to once every five years for some time). These only allow exceptions in specific circumstances – such as aligning your accounting dates with a UK parent or subsidiary, being in administration, or having approval from the Secretary of State. If reintroduced, the shortening rules may follow a similar framework.
How changing your ARD affects HMRC and Corporation Tax
Changing your accounting reference date doesn’t just affect Companies House. It will also change your accounting period for Corporation Tax, meaning your Corporation Tax payment deadlines and your Company Tax Return filing deadlines with HMRC will differ.
When you change your ARD, this can mean:
- Your Corporation Tax period becomes shorter or longer, which may require you to submit more than one tax return if it runs over 12 months
- Your deadlines for filing your Company Tax Return and paying Corporation Tax may change
- You may need to update HMRC’s records if your tax period no longer matches your financial year
You can check your Corporation Tax accounting period by signing in to your business tax account on HMRC’s online service. If your accounting period and financial year no longer align as a result of the change, you may need to contact HMRC to update your records before filing your next return.
How to apply for a Companies House deadline extension
If an exceptional and unforeseeable event prevents you from filing your company accounts on time, you can make a formal application to Companies House asking for more time. This is separate from changing your ARD – it’s a direct request to extend your existing filing deadline.
When can you apply?
You must submit your application before your normal filing deadline. Companies House will not consider requests made after the deadline has passed, and late filing penalties are applied automatically from the day after your deadline.
The keyword here is “exceptional.” Companies House will not usually grant extensions for reasons like forgetting the deadline, your accountant being busy, or general workload pressures. Accepted reasons typically include fire, flooding, theft, serious illness, or bereavement – events genuinely outside your control.
What you need to include in your application
To apply online – which is the quickest route – you’ll need the following:
- Your company registration number
- An email address
- A clear explanation of why an extension is needed, with as much detail as possible
- Supporting documents, if you have them – these are optional but can strengthen your case
You can apply through the Companies House extension service. Given the time-sensitive nature of these requests, applying online is often the better option than posting a paper form.
How long does approval take?
Companies House will contact you with a decision. If Companies House approves your request, you’ll receive an extension decided on a case-by-case basis, but often 30 days.
Keep in mind that the extension only applies to the current set of accounts. Your filing deadline for the following year remains unchanged, so make a note of it to avoid falling behind again. If the new deadline is not met, normal late filing penalties will apply.
What happens if you miss the filing deadline?
If you can’t extend your application or it’s refused, your deadlines will remain unchanged. Late filing penalties are automatic – Companies House doesn’t send a warning first. The penalties for private limited companies are:
- 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
If your accounts are late two years in a row, these penalties double, so a six-month delay could cost you £3,000.
The criminal consequences of late filing
Beyond the penalties, late filing is a criminal offence. Directors who show a track record of non-compliance or wilful disregard for their obligations can face prosecution, personal fines or disqualification from acting as a director for up to 15 years under the Company Directors Disqualification Act 1986. Companies House can also strike your company off the register, which means the company ceases to exist and its assets pass to the Crown.
The potential impact on your company’s public record
Late filing affects your company’s public record, as Companies House records when your accounts are late. Credit reference agencies monitor Companies House data, so missed deadlines can, in theory, damage your credit score and make it harder to secure loans, credit, or favourable supplier terms.
The message is clear – it’s always better to act before the deadline than deal with the consequences after.
Choosing between changing your ARD and requesting an extension
If you’re not sure which route is right for you, here’s a quick comparison:
| Factor | Changing your accounting reference date (ARD) | Requesting a deadline extension |
|---|---|---|
| Main purpose | Aligning with a group, matching trading cycles, tax planning, improving reporting timelines, or managing one-off timing issues | To deal with a genuine, unexpected problem (fire, flood, theft, serious illness, bereavement, or major disruption) |
| Use for deadline management | Can sometimes extend your filing deadline if timed correctly | Directly extends your existing deadline if approved |
| Level of control | You choose when and how to make the change | Companies House decides whether to approve |
| Approval needed | No formal approval if the rules are followed, unless the now paused changes go ahead at some point in the future | Yes – approval is required |
| Impact on financial year | Changes the length and end date of your accounting period | No change to your accounting period |
| Impact on HMRC deadlines | May affect Corporation Tax periods and payment dates | No effect on HMRC deadlines |
| Suitability for regular use | Best for occasional or long-term planning, not repeated short-term delays | Only suitable for genuine emergencies |
| Risk of refusal | Low if conditions are met | Possible if the reason is not accepted |
| Long-term implications | Affects future reporting cycles and may be restricted under future rules | Applies only to the current year |
In some cases, you might use both. For example, you might shorten your ARD by a day to buy three months of extra time, and then if something genuinely exceptional happens before the new deadline, you could apply for an extension on top of that.
But be careful not to take these mechanisms lightly – they could present unforeseen complications if you don’t handle them appropriately.
Keeping on top of your company accounts
Filing your accounts on time is one of the most important ongoing obligations of a registered company.
While changing your ARD or applying for an extension can help when something hasn’t gone to plan, they’re not a fallback for regular delays. Using them too often can make it harder to depend on them when you genuinely need extra time.
From April 2027, new restrictions on changing accounting reference dates are expected to reduce how much flexibility companies have around filing deadlines. Giving yourself enough time to prepare your accounts will become even more critical.
If you need help staying compliant, our Full Company Secretary Service provides ongoing support with filings, deadlines, and company secretarial duties – so you can focus on running your business.
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