Key takeaways

  • You can only get more time to file accounts if something outside your control, such as serious illness or a fire that destroys records, stops you filing on time.
  • You must apply before your filing deadline; once accounts are overdue, Companies House cannot extend the deadline and a penalty follows.
  • The law caps any extension so the filing deadline is no later than 12 months after the end of the accounting reference period.
  • Apply through the Companies House online extension service, which needs your company number, an email address and your reasons, and takes up to 15 minutes.
  • Private companies normally have 9 months after their year end to file, and public companies have 6 months.
  • Late filing penalties for a private company run from £150 to £1,500, and double if accounts are late two years running.
  • Extending your accounting reference date with form AA01 also moves the deadline, but a period cannot exceed 18 months and you can usually extend only once in five years.

You can ask Companies House for more time to file your company’s accounts, but only if an event outside your control stops you filing, and only if you apply before the deadline. Apply online using the Companies House extension service; it takes about 15 minutes. If your reason is simply that you are busy or your accountant is late, the application will almost certainly fail, so look at the other options below.

Who can get an extension?

Companies House grants extensions only where something outside your control stops you filing on time. Its guidance on applying for more time gives two examples: an unexpected illness, and a fire that destroys company records shortly before the deadline.

The legal power sits in section 442(5) of the Companies Act 2006. It lets the registrar extend the period for a company that applies before the period expires, if there is a “special reason”.

You may not be eligible if you have already extended your deadline, or if you have shortened your accounting period.

What reasons are unlikely to work?

Companies House’s late filing penalties guidance lists reasons that are unlikely to succeed on their own. They are a fair guide to what will not support an extension either.

  • The company is dormant
  • You cannot afford to pay
  • Your accountant was ill, or you relied on them
  • These are your first accounts
  • You did not know the filing rules
  • Financial difficulties, including bankruptcy
  • Accounts were delayed or lost in the post
  • Directors were overseas or travelling
  • Another director prepared the accounts

How do you apply?

You apply online through the Companies House extension service, or by letter. Follow these steps.

  1. Check your deadline. Look up the company on the Companies House register. You do not need to phone to confirm it.
  2. Gather your evidence. Write a full explanation of what happened and how much more time you need. Add supporting documents if you have them, such as a medical letter or fire report.
  3. Apply before the deadline. Use the online service with your company number and an email address. It takes up to 15 minutes.
  4. Or write to Companies House. Send your letter to Companies House, Crown Way, Cardiff, CF14 3UZ (DX 33050 Cardiff). Allow for postal delays, because the application must arrive before the deadline.
  5. Keep working on the accounts. Companies House says you should not wait for a decision. File as soon as you can.
  6. Read the decision email. Companies House will email the outcome and may ask for more information. You may still get a chasing letter while it decides.

How much extra time can you get?

The law caps any extension so the deadline is no later than 12 months after the end of the accounting reference period, under section 442(5A). A private company normally has 9 months, so the most extra time it can get is about 3 months.

Company typeNormal deadline after year endMaximum with extension
Private company9 months12 months
Public company6 months12 months

An approved extension applies to that set of accounts only. It does not move your future deadlines. Check your normal dates with our filing deadline calculator.

What if you miss the deadline anyway?

Companies House issues an automatic penalty once accounts are late, and it cannot extend a deadline that has already passed. Penalties for a private company or LLP are:

How latePrivate company or LLPPublic company
Up to 1 month£150£750
1 to 3 months£375£1,500
3 to 6 months£750£3,000
Over 6 months£1,500£7,500

The penalty doubles if accounts are late in two successive financial years. Our Companies House late filing penalties guide explains how to appeal. Persistent non-filing can also lead to a compulsory strike-off notice.

Is changing your year end a better option?

Extending your accounting reference date (ARD) on form AA01 also moves the filing deadline, and it does not need a special reason. Companies House’s accounts guidance, updated 23 October 2026, sets the limits.

  • An accounting period cannot last more than 18 months from its start.
  • You can usually extend only once in five years, unless the company is in administration or aligning with a UK parent or subsidiary.
  • You must file the AA01 before the current filing deadline. Once accounts are overdue, it is too late.
  • Do not just add 6 months to a 12-month period near its end; you may breach the 18-month limit.

Which option applies to you?

  • If illness, fire, flood or another event outside your control has stopped you, apply for an extension before the deadline.
  • If you simply need a different year end, consider extending the ARD with form AA01, within the 18-month and five-year limits.
  • If the deadline has passed, file immediately to keep the penalty in the lowest band, then consider an appeal.
  • If you are worried about the Corporation Tax return, note that an extension at Companies House does not change HMRC deadlines.

What to do now

  1. Look up your deadline today on the Companies House register.
  2. If you cannot file in time for a reason outside your control, apply online straight away.
  3. Brief your accountant; see our guide on how to file accounts with Companies House.
  4. Plan for 1 April 2028, when all accounts must be filed through commercial software.

Frequently asked questions

Can I extend my Companies House accounts deadline?

Yes, if an event outside your control stops you filing and you apply before the deadline. Companies House decides each application and emails you the result.

How long is a Companies House filing extension?

It depends on your reasons, but the law caps the filing period at 12 months after the end of the accounting reference period. For a private company that is at most about 3 months extra.

Can I apply for an extension after the deadline?

No. You must apply, or file, before the deadline. After that, Companies House issues an automatic late filing penalty.

Does an extension cost anything?

The Companies House guidance does not mention a fee for applying, and the online service asks only for your company number, email address and reasons.

Does a Companies House extension also extend my Corporation Tax deadline?

No. Companies House and HMRC deadlines are separate. Your Company Tax Return and Corporation Tax payment dates do not move.

Sources

Rates, thresholds and rules in this guide were checked against HMRC and GOV.UK guidance on 6 November 2026. Tax rules change, so check the current position on GOV.UK or with a qualified adviser before acting. This guide is general information, not personal advice.