From 23/24, you’ll need to use the standard financial year. [Basis Period Information]
Your accounting period usually starts from when your self employment commences, and normally runs from this date for a period of 12 months.
For example, if you started on 14 November, your accounting period would run for 12 months, until 13 November the following year.
However HMRC run their ‘standard’ accounting period from the 6 April until the 5 April the following year, meaning that having different dates on your own accounting period than HMRC’s can cause confusion. You can view tax year examples here.
As a sole trader, you can change your accounting date for tax purposes on your self assessment tax return. When completing the return for your shorter period, you can provide the dates of your ‘short’ tax year which took place before moving to the standard 12 month period.
You may need to provide a short reason why the change is happening – you can simply advise you’re moving to the standard tax year period.