UK company year end (financial year end): Accounting Reference Date (ARD), month-end, and filing deadlines
If you’re a new UK company owner, your company year end date (also called financial year end) can feel confusing. This guide explains the Companies House Accounting Reference Date (ARD) with simple examples and key deadlines.
In This Guide
1. What is an Accounting Reference Date (ARD)?
Your Accounting Reference Date (ARD) is your Companies House financial year end date. It’s the date your statutory accounts are “made up to”.
Plain English
Think of ARD as your “year end”. Your accounts cover everything from the start of the period up to that date.
2. Why is it often the last day of a month?
For many newly incorporated UK companies, the default year end is set to the last day of the incorporation month. That’s why you’ll often see month-end dates like 31 January, 30 June, 30 November, etc.
First period can be longer
Your first set of accounts can cover a longer period than 12 months (often up to 18 months), so your first filing deadlines can be different from “normal years”.
3. Key deadlines (Companies House + HMRC)
| Requirement | Submitted to | Typical deadline |
|---|---|---|
| Annual accounts (later years) | Companies House | 9 months after year end |
| First accounts | Companies House | Often 21 months after incorporation |
| Company Tax Return (CT600) | HMRC | 12 months after the accounting period end |
| Corporation Tax payment | HMRC | 9 months + 1 day after period end |
Source & further reading: GOV.UK – Prepare annual accounts
4. Worked examples
Example A: incorporated mid-month
- Incorporated: 15 Nov 2025
- Default year end month: November (month-end ARD)
- ARD: 30 Nov 2026
- Companies House accounts deadline (typical): 9 months after year end → 31 Aug 2027
Example B: incorporated at month-end
- Incorporated: 31 Jan 2026
- ARD: 31 Jan 2027
- Annual accounts deadline (later years): 31 Oct
5. Can I change my year end?
Yes — you can usually shorten your accounting period, and you can extend it in limited cases. Changing your year end affects the length of the period and therefore your filing deadlines.
If you are choosing a year end for convenience, many founders pick a month-end that aligns with their business cycle (for example, after a quieter month) — but it’s often best to keep it simple and avoid unnecessary changes.
6. FAQs
Where can I find my ARD?
You can find it in your Companies House profile (or confirmation emails from incorporation), and many accounting tools show it as “year end”.
Is ARD the same as the HMRC accounting period?
Often they align, but not always. Your statutory accounts (Companies House) and your Corporation Tax return (HMRC) are related but have separate rules and deadlines.
What happens if I file late?
Companies House applies automatic penalties if you file accounts late. See GOV.UK – penalties for late filing .