Forming your company is a great first step towards achieving your business goals. But learning about accounting periods can feel challenging. Some critical early questions are, “what is my company’s financial year, can I change it and how?”
Think of your financial year as a standard 12-month cycle during which you track all your business activities, income, expenses and profit.
At the end of the year, you’ll use this information to prepare your annual accounts, which you must send to Companies House.
The last day of your financial year is referred to as the accounting reference date (ARD) . It’s a critical marker, because you must make up your annual accounts to this date, or a date seven days either side of the ARD if you prefer. This reference also dictates your deadlines for filing annual accounts and Company Tax Returns.
Companies House automatically provides your accounting reference date shortly after incorporation. For most, the date will be one year after the last day of the month in which the company is registered .
In your first year of trading, your reporting period will begin on the day of incorporation and run up to your designated ARD, so it will usually be slightly more than 12 months. However, in the years that follow, it will be exactly 12 months, unless you change your ARD.
Say you registered your business on 2 October 2026:
Don’t worry if your designated ARD doesn’t match with your reporting schedules, workflows or tax plans. You can alter your ARD, provided your annual accounts aren’t already overdue. You can only change the year-end date for the current or previous year.
If you need to move your ARD forward (making your current year shorter), the rules are flexible. You can shorten the year by any number of months or days – even by just one day. You can do this as often as needed. The exception is that you cannot shorten the period if you’re submitting your first Companies House filing.
If you need more time to submit your account s, you can extend your financial period up to a maximum of 18 months from your previous ARD, or longer if you’re in administration. But you can only lengthen it once every five years, unless:
The options for registering a change in ARD are:
Rapid Formations allows you to update the ARD in your admin portal, then we’ll handle the filing for you. If you’re not already a Rapid Formations client, you can easily create a free account, import your information, and then alter your ARD in our system.
Adjusting your year-end date directly affects your Corporation Tax accounting period, so you need to tell HMRC about the alteration to ensure your tax records align with your new ARD.
If you extend your financial year beyond the standard 12 months, you’ll need to send two separate Company Tax Returns because your accounting period cannot be longer than 12 months.
Preparing two tax returns might sound daunting, but it’s crucial for compliance and ensures your tax is calculated correctly for each period.
Your annual accounts period is important, so why change it? The main reasons companies do this are:
The deadline for sending annual accounts to Companies House is nine months after your ARD. To check your due date, the company information service displays it on your overview screen. You can also register for emailed deadline reminders.
The deadline for submitting your Company Tax Return (a separate document, sent to HMRC, that must include full accounts) is 12 months after the end of your company tax accounting period. This period may or may not align with your financial year. So, aligning your accounting period and financial year is another potential reason for changing your ARD. Filing them together is a great way to simplify your reporting.
Ultimately, whether you choose to alter your financial year depends on your unique business model and reporting cycles. Once you’re up and running, you’ll get a feel for whether a change can help you forge a more predictable and manageable rhythm in your business.
Ready to take control of your company’s compliance? Explore our Hassle-Free Compliance Service for expert ongoing support.
Your accounting period for Corporation Tax is the time covered by your Company Tax Return. Sign in to your business tax account to check these dates for your company.
You need to deliver acceptable accounts on time, or you will receive a late submission penalty . The penalty ranges from £150 to £1,500 for private companies, depending on the lateness of your submission.
You can appeal online . You’ll need: