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Companies House guide

Can I change my company accounting reference date?

A company can change its accounting reference date in some circumstances, but timing and extension restrictions matter.

Last reviewed
18 July 2026
Sources checked
18 July 2026
Reading time
6 minutes

Written by Business Sorted editorial team

Business Sorted provides general educational information and organisation tools. It is not Companies House, HMRC, a solicitor, an accountant, a tax adviser or a regulated professional adviser. Check official sources and get professional advice where your circumstances need it.

Direct answer

Companies House guidance says a company can change the current or immediately previous accounting reference date by filing online, using software or sending form AA01. The change must be made before the filing deadline for the accounts period being changed.

Key facts

  • Companies House uses form AA01 or online/software filing to change the accounting reference date.
  • The change must be made before the accounts filing deadline for the period being changed.
  • An accounting period usually cannot be extended beyond 18 months unless an exception applies.
  • Changing the date can create a new filing deadline and may trigger a penalty if that deadline has already passed.

When you can change it

Companies House guidance says you can change the current or immediately previous accounting reference date. You can file the change online, use software or send paper form AA01.

You must do this before the filing deadline for the accounts period you want to change. If the accounts are already overdue, Companies House says it is too late to change the accounting reference date for that period.

Restrictions to check

There are restrictions on extending accounting periods. Companies House guidance says you cannot extend a period so that it lasts more than 18 months from the start date of the accounting period, unless an exception applies.

The guidance also explains restrictions on extending more than once in 5 years. From 1 April 2028, Companies House says a business reason will be needed if a company wants to shorten the accounting reference period more than once in 5 years, subject to forthcoming regulations.

How a change can affect deadlines

Changing the accounting reference date can change the accounts filing deadline. If the new deadline has already passed when the date is changed, Companies House guidance says the company will get an automatic late filing penalty.

Before changing the date, check whether it helps or creates a new deadline problem. This is an area where accountant input may be useful.

Frequently asked questions

Can I change the accounting reference date after accounts are overdue?

Companies House guidance says if your accounts are overdue, it is too late to change the accounting reference date for that period.

Does changing the accounting reference date remove an accounts deadline?

No. It changes the accounting period and can change the deadline, but it can also create a penalty risk if the new deadline has passed.

Related guides

What is a company's accounting reference date?Understand what the accounting reference date means for Companies House accounts and why directors should check it before planning filings.Annual accounts guide for UK limited company directorsUnderstand what annual accounts are, common Companies House filing deadlines and how accounts differ from HMRC Company Tax Returns.When are first company accounts due?Understand the special first accounts deadline for private limited companies and why it can differ from later annual accounts deadlines.What happens if company accounts are filed late?Understand the practical Companies House consequences of late company accounts and the next steps directors should consider.

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