A Corporation Tax return (also known as a CT600) is a form that companies registered in the UK must submit to HM Revenue and Customs (HMRC) to report their income, minus any tax allowances and expenses. This form is used to calculate the amount of Corporation Tax your company owes.
How do I file a Corporation Tax return?
- Prepare your company's annual accounts. These should include a profit and loss account, a balance sheet and any necessary accompanying notes
- Calculate your taxable profits. This is your company's income, minus any tax allowances and expenses. This may not be the same as the profit shown in your annual accounts
- Complete your Corporation Tax return. This is where you report your taxable profits and calculate your Corporation Tax bill. The form you need to complete is the CT600, which can be found on the HMRC website
- Submit your Corporation Tax return. The deadline for submitting your return is 12 months after the end of the accounting period it covers
Note that even if your company makes a loss or has no Corporation Tax to pay, you still need to file a Corporation Tax return if you receive a 'notice to deliver a Company Tax Return' from HMRC.
First year and subsequent years
The process of filing tax returns for your company is different in your first year of trading and subsequent years. This is due to the alignment of your company's accounting period with the Corporation Tax accounting period.
In your first year of trading your company's accounting period starts on the day your company was set up (incorporated or registered), and ends on the accounting reference date set by Companies House. This date is the last day of the month in which the company was set up. For example, if your company was set up on 11 May the accounting reference date will be 31 May the following year, and your company’s first accounts must cover 12 months and 3 weeks.
However, the period covered by your tax return (your ‘accounting period’ for Corporation Tax) cannot be longer than 12 months. This means you may have to file 2 tax returns to cover the period of your first accounts. For instance, if your company started trading on the same day it was set up, you would file one tax return for your company’s first 12 months, and one for the rest of the time covered by your company’s first accounts.
In subsequent years, your accounts and tax returns will normally cover your company’s financial year from 1 June to 31 May (following the example dates above), and you’ll typically only need to file one tax return.
In summary, the key difference between the first year and subsequent years is the potential need to file two tax returns in the first year due to the alignment of the company's accounting period with the Corporation Tax accounting period.
Learn more about filing your Corporation Tax return on gov.uk