UK Financial Year End: Accounting Reference Date & Filing Deadlines
Every company incorporated in the UK with Companies House is automatically assigned a Financial Year End, formally known as the Accounting Reference Date (ARD). The Financial Year End determines your statutory accounts filing deadlines, Corporation Tax obligations, and overall annual compliance cycle.
Under the Companies Act 2006, failing to meet statutory filing deadlines can result in automatic penalties. Understanding your UK company’s Financial Year End is therefore essential for maintaining ongoing legal and tax compliance.
This guide explains how a Financial Year End is determined, the key filing deadlines UK companies must follow, and how to change your company’s Accounting Reference Date when necessary.
What Is a Company’s Financial Year-End in The UK?
The financial year end of a UK company, also referred to as the Accounting Reference Date (ARD), is the final day of the company’s 12-month accounting period. It is the date to which all annual accounts must be prepared and submitted. For directors and company secretaries, this date anchors every statutory filing obligation the company holds.
- Governed by Sections 390-392 of the Companies Act 2006
- Assigned automatically by Companies House upon incorporation
- Set as the last day of the month in which the first anniversary of incorporation falls
- Directors may end the financial year up to seven days before or after the formal ARD under Section 390(2), without requiring a formal change
If your company is incorporated on 14 March 2025, your ARD will be set as 31 March 2026, a period slightly longer than 12 months. From the second year onwards, the cycle runs from 1 April to 31 March each year.
Why Is the First Accounting Period Is Usually Longer Than 12 Months?
Companies House sets the ARD at the end of the month of the first anniversary, not the anniversary date itself, which means the first period will almost always exceed 12 months.
- The first period must be more than six months but no more than 18 months
- Where it exceeds 12 months, HMRC splits it into two separate Corporation Tax accounting periods
- Each period requires a separate CT600 filing with its own payment deadline
- Directors should plan for two potential tax settlements in the first year to maintain adequate cash flow
What Are The Statutory Accounts Filing Deadlines for UK Companies?
Once your ARD is established, your company faces two parallel but distinct sets of filing obligations: one to Companies House and one to HMRC. These are governed by separate legislation and carry separate deadlines and penalties.
1. Companies House: Statutory Accounts Deadlines
- Private Limited Company (Ltd) annual accounts due 9 months after the ARD; first accounts due 21 months from the date of incorporation
- Public Limited Company (PLC) annual accounts due 6 months after the ARD; first accounts due 18 months from the date of incorporation
A private limited company with an ARD of 31 March 2025 must file its statutory accounts with Companies House no later than 31 December 2025. For first-time filers, the 21-month window provides additional preparation time, but the deadline is strictly enforced. A private company incorporated on 1 January 2025 with an ARD of 31 January has until midnight on 1 October 2026 to deliver its first accounts.
2. HMRC: Corporation Tax Deadlines
Corporation Tax obligations run on a separate timetable from Companies House filings:
- Corporation Tax payment due 9 months and 1 day after the end of the accounting period
- Company Tax Return (CT600) filing due 12 months after the end of the accounting period
The payment deadline falls before the filing deadline. For a company with a 31 March 2025 year end, Corporation Tax must be paid by 1 January 2026 even though the CT600 return is not due until 31 March 2026. Directors must ensure funds are reserved accordingly.
3. Late Filing Penalties: Companies House (Private Limited Companies)
Missing even a single day triggers an automatic penalty. These penalties double if accounts are filed late for two consecutive years:
- 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
Companies House applies these penalties automatically upon the filing deadline being exceeded. No advance notice is issued; the obligation to file on time rests entirely with the company’s directors.
How to Change Your Company’s Financial Year-End (Accounting Reference Date)?
UK company law permits directors to change their company’s ARD, subject to specific statutory limitations. This is one of the most strategically useful tools available to company directors, enabling alignment with parent company reporting cycles, UK tax year dates, or the company’s natural business cycle.
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When Is It Permissible to Change the ARD?
A change to the accounting reference date can only be made before the accounts filing deadline for the relevant period. It must apply to the current or immediately preceding accounting reference period, and the accounts for that period must not already be overdue. If any of these conditions are not met, the ARD cannot be changed for that period
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How to Apply: Form AA01
Directors must file Form AA01 with Companies House either online via the Companies House filing service or by post. The form requires directors to confirm whether the period is being shortened or extended and to specify the new ARD. A director’s resolution approving the change must be in place before submission.
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Shortening the Financial Year
The financial year may be shortened as many times as required and by any number of days or months. There are no restrictions on frequency, making this the more flexible of the two options. The only exception is that the financial year cannot be shortened during the first filing period.
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Extending the Financial Year
An extension is capped at a maximum of 18 months from the start of the accounting period and is permitted only once every five years. The exception to this restriction applies where the new ARD aligns with a parent or subsidiary undertaking’s year-end, as provided under Section 392(3) of the Companies Act 2006, in which case the five-year rule does not apply.
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Strategic Considerations When Choosing Your ARD
The most common year-end dates for UK limited companies are 31 March and 5 April, aligning with the government’s financial year and personal tax year. The optimal date, however, depends on trading patterns, cash flow timing, VAT quarter alignment, and group reporting requirements.
Any change to the ARD must be separately notified to HMRC, as it does not automatically update the Corporation Tax accounting period. Professional accounting advice is strongly recommended before altering an established ARD.
How to Find Your Company’s Accounting Reference Date?
Your company’s ARD is publicly available and can be checked at any time:
- Visit the Companies House Company Search
- Search for your company by name or registration number
- Navigate to the Filing History or Overview tab
- Your ARD and next filing deadline will be listed under your company’s details
Your ARD will also appear on any correspondence received from Companies House following incorporation, and within your company’s registered accounting software if correctly configured.
Leave Your Financial Year-End in Expert Hands With 3E Accounting
Determining the correct financial year-end at incorporation and managing the accounting reference date strategically thereafter establishes the foundation for every annual compliance obligation your company will face. Directors who approach this with expert support avoid the penalties and disruption that accompany missed statutory deadlines.
3E Accounting is a specialist UK incorporation and accounting firm offering end-to-end compliance support from company formation right through to statutory accounts preparation and HMRC Corporation Tax filings.
