Change of Accounting Reference Date

The accounting reference date (ARD) plays a central role in your company’s financial reporting. It determines your financial year end and the deadline for filing accounts with Companies House and HMRC.

Sometimes, a business may need to change its accounting reference date — whether to align with a parent company, the tax year, or seasonal trading patterns. Knowing how and when to do this, and what it affects, is essential to staying compliant and organised.

What Is an Accounting Reference Date?

The accounting reference date is the official end of a company’s financial year, set by Companies House. It’s used to determine when your annual accounts are due.

By default, the ARD falls on the last day of the month in which your company was incorporated. So if you incorporated on 12 May 2024, your first accounting reference date will be 31 May 2025.

Is the Accounting Reference Date the Same as the Company’s Financial Year End?

Yes — in most cases, the accounting reference date and the financial year end are the same thing. It marks the closing date of the period your accounts will cover.

Internally, some companies may run management accounts or reporting cycles based on different dates, but legally and for filing purposes, your ARD is your company’s financial year end.

Where Do I Find the Accounting Reference Date for My Company?

You can find your company’s accounting reference date by checking:

• Your Companies House record

• Your incorporation certificate

• Previous annual accounts

• Your company’s Confirmation Statement

Alternatively, search your business name on the Companies House register and check the "Next accounts made up to" date.

Why Is My Accounting Reference Date Important?

The ARD is important because it sets your filing deadlines and defines the financial period you report on each year.

If you miss the deadline for submitting accounts to Companies House or HMRC, you can face automatic late filing penalties. It also affects when corporation tax is due and when you need to prepare for audits or internal reviews.

Changing the date can help align your reporting with:

• Your tax year (ending 5 April)

• Your group of companies

• Your business cycle or peak trading periods

How Long Is a Company’s Financial Year?

A company’s financial year usually lasts 12 months, starting from either the incorporation date or the day after the previous financial year ended.

For the first year, your financial period can be up to 18 months, depending on when you choose to file your first set of accounts.

After that, it typically stays as a 12-month cycle unless changed.

What Are the Reporting Deadlines with HMRC and Companies House?

For Companies House, you must file:

• First accounts: within 21 months of incorporation

• Annual accounts (after the first): within 9 months of your ARD

For HMRC, you must:                      

• File your Company Tax Return within 12 months of your financial year end

• Pay any Corporation Tax within 9 months and 1 day of the year end

If you change your ARD, it will reset your Companies House deadline — but not always your HMRC deadline, so you may need to notify HMRC separately if the period changes.

How Do I Change My Accounting Reference Date?

You can change your ARD by:

1. Logging into your Companies House online account

2. Submitting a Change of Accounting Reference Date form

3. Selecting whether you are shortening or extending your accounting period

This can also be done by post using form AA01, but online filing is quicker.

You can:

• Extend your financial year once every five years, unless there’s a valid reason

• Shorten it as many times as you like

You cannot extend the period if your accounts are already overdue.

Why Would I Change My Accounting Reference Date?

There are a few common reasons why businesses change their ARD:

• To match the tax year (ending 5 April) for easier tax planning

• To align with a parent company’s group reporting

• To suit seasonal trading cycles (e.g. retailers finishing accounts after Christmas)

• To simplify reporting or cash flow forecasting

• When planning for business closure or restructuring

Changing your date gives you flexibility to align reporting with how your business actually operates.

Final Thoughts

Your accounting reference date isn’t just an administrative detail — it controls the entire rhythm of your financial year. Knowing when and how to change it can help you plan more effectively, avoid penalties, and stay in control of your reporting obligations.

If you're considering a change, make sure it's done properly through Companies House, and don’t forget to review your corporation tax timelines with HMRC at the same time.