The rules in brief
- Shortening: allowed as often as you want, by as little as one day
- Lengthening: normally only once every five years, and a period can never exceed 18 months (limited exceptions, e.g. administration)
- Not overdue: you can’t change the date for a period whose accounts are already late
The change is made on form AA01, free and usually processed quickly online.
Why directors change the date
- Align to 31 March — so the company year matches the tax year and calculations are cleaner
- Pick a quieter month — easier stocktakes and year-end admin when trade is slow
- Match a group — line a subsidiary up with its parent
- Tax timing — occasionally, to shift when a liability falls
Watch the deadline shift
Changing the year end recalculates your filing deadline from the new date — broadly the longer of the normal deadline or three months from when you notify Companies House. Shortening tends to bring accounts forward; lengthening pushes them back. Always confirm the new due date straight after the change so nothing slips.
We'll handle the change and the knock-ons
If a different year end would suit your company, we’ll advise, file the AA01 and re-diarise every affected deadline — and adjust the accounts and Corporation Tax periods accordingly. Call 0114 327 1480.