How to Change Your Accounting Reference Date (ARD) to Extend Filing Deadlines

If your accounts deadline is approaching and you need more time to prepare them properly, one option is to change your company’s accounting reference date (ARD). This is the date your financial year ends each year, and adjusting it can extend your filing window with Companies House. Many directors use this approach when things get busy or accounts take longer than expected.

Note that this works best for shortening the period (which can paradoxically give extra time in some cases) or lengthening it carefully. There are rules and limits, so let’s walk through how it works in 2026.

What is the Accounting Reference Date (ARD)?

Your ARD is the end date of your financial year. Companies House sets it automatically after incorporation – usually the last day of the month in which your company was incorporated, one year later.

For example:

  • Incorporated 15 April 2025 → ARD is 30 April 2026.
  • Accounts due 9 months later: 31 January 2027 (for private companies).

Changing the ARD shifts your year-end and, in turn, your accounts filing deadline.

When and Why You Might Want to Change It

Common reasons include:

  • Needing extra preparation time for accounts.
  • Aligning your year-end with your business cycle (seasonal trade, group reporting).
  • Avoiding a busy period for your accountant.

You can change the ARD for your current financial year or the one just ended (if accounts not yet filed). You cannot change it if accounts are already overdue.

Rules and Restrictions in 2026

  • Shortening the period (bringing ARD forward): Allowed as often as needed now, but from 1 April 2027, you’ll need a business reason if shortening more than once in 5 years.
  • Lengthening the period (pushing ARD back): Limited to 18 months max for the first period (unless in administration). Cannot exceed 18 months in most cases.
  • No change if accounts overdue.
  • File before the current deadline.

When you shorten the ARD, the new filing deadline becomes the later of:

  • 9 months from the new ARD, or
  • 3 months from when Companies House receives your application.

This can give you breathing room if filed close to the original deadline.

For lengthening, the deadline shifts to 9 months after the new later ARD.

How to Change Your ARD Step-by-Step

  1. Check your current ARD and deadline on your company page at find-and-update.company-information.service.gov.uk. Search your company name or number – no login needed.
  2. Decide on the new date. Make sure it fits the rules (current or previous period, no overdue accounts).
  3. File form AA01:
    • Online (easiest and fastest): Use the Companies House online service. Log in with your authentication code or GOV.UK One Login. Select the change accounting reference date option and enter details.
    • By post: Download form AA01 from GOV.UK, fill it in, and send to the address on the form.
  4. Submit before your current accounts deadline. Companies House usually processes quickly (days for online).
  5. Once approved, your new ARD appears on your company page, and the deadline updates.

No fee for this change.

Things to Watch Out For

  • It affects Corporation Tax periods too – notify HMRC if needed.
  • If lengthening, ensure the new period does not go over 18 months (exceptions rare).
  • Plan ahead: Last-minute changes work, but give time for processing.
  • Future changes: From April 2027, accounts filing moves to software only, so software might handle ARD changes alongside.

If you’re tracking multiple deadlines or want to see how a change impacts your dates quickly, tools that show your current ARD and upcoming obligations help. Companies House on the Go from Touch of Class pulls public company data fast on your phone. You can check your ARD, see filing deadlines, and monitor for several companies without constant website searches. It’s a practical way many directors keep organised.

For simple ways to stay on top of your company details, check out Companies on the Go.

Final Thoughts

Changing your ARD is a legitimate way to gain time or align your year better, as long as you follow the rules and act before deadlines. It’s not a fix for repeated delays, but useful when genuine need arises.

Next time your deadline feels tight, look at your ARD on the Companies House site. A quick AA01 could make all the difference.

Download the app for easy checks on the go:

iOS version or

Android version.