CTM92600 | CTSA: quarterly instalments: amount due at each instalment: formula

From HM Revenue & Customs · Company Taxation Manual

The amount of tax to be paid at each instalment date is:

3 x CTI
n

Where:

  • ‘CTI’ is the amount of the company’s total liability, as described in for the accounting period that is payable by instalments.

  • ‘n’ is the number of months in the accounting period.

    Part months are calculated by dividing the number of spare days by 30 and expressing the sum as a decimal to two places, rounded arithmetically.