Accounting periods for Corporation Tax

Your ‘accounting period’ for Corporation Tax is the time covered by your Company Tax Return.

It cannot be longer than 12 months and is normally the same as the financial year covered by your company or association’s annual accounts. It may be different in the year you set up your company.

Your accounting period affects your deadlines for paying Corporation Tax and sending (‘filing’) a Company Tax Return.

Check your accounting period

Sign in to your business tax account using HM Revenue and Customs’ (HMRC’s) online service to check the dates of your accounting period.

Your first accounting period

You’ll get a letter from HMRC giving you dates for your accounting period, after you add Corporation Tax services to your business tax account.

Tell HMRC if you think the dates are wrong.

If your accounting period and financial year are different

Check what to do if your accounting period is different from your financial year:

• in your first year of business
• when you restart your business
• if you stop trading and become dormant

Your accounting period can also be different to your financial year when your accounts cover:

• more than 12 months, for example after you lengthen your company year
• less than 12 months, for example after you close your company or shorten your company year

If your accounts cover more than 12 months

You must file 2 returns to cover the period of your accounts because your accounting period cannot be longer than 12 months.

If you’ve lengthened your company’s financial year, you need to update your accounting period dates. To do this you must contact HMRC before the original filing date of your Company Tax return.

Example

Your company’s year end is 31 December 2023 and you lengthen it to 31 March 2024. You would need to update your accounting period dates with HMRC before 31 December 2024 and file all returns by 31 March 2025.

You may get a late filing penalty if you do not update your accounting period dates with HMRC.

If your accounts cover less than 12 months

Your accounting period normally ends on the same day, so will also be shorter than 12 months.

If you use HMRC’s online service to file your Company Tax Return, contact HMRC to update your accounting period dates before you file your return.

If you use accounting software to file your Company Tax Return, enter the new dates for your accounting period before you file your return.