# [Gantt] How to change the calculation percentage on parent task

Is there a way to change the default calculation of parent percentage? Due to my use case the method which is default is actually not applicable for my items, because some of then open and close in the same day, so parent percentage does not reflect actual completion (2/5 items closed = 40%)

Here’s an Example: In the case below we have 16 items (13 are considered closed, while 3 are not) I want to report 81.25% (13/16).

Since those items already completed have the same date for when they were open and closed, in the default calculation we get a multiplication by 0, showing that this project is 0% complete.

Gabriel Reis Asked question