Roll up tasks Wrong value

Holger K. shared this question 8 months ago
Discussion Open

I have created a branch (level 01) in Tasks Unroll Tasks
Unfortunately, an incorrect value is displayed and not correct as it should be

Replies (4)


The rolled-up duration is not the sum of durations. It is the duration from the start of the earliest task to the end of the latest task.


Further to Nick's response, in your example the tasks all start on the same date and run concurrently, so the end date and therefore the duration of the rolled-up project will be determined by the end date of the task with the longest duration, in this case Design Process.

If you intend the tasks to run consecutively you will have to establish relationships between them and set the type of dependency, for example, Finish to Start. This will set the task start and due dates automatically, and therefore set the duration. In turn the duration of the rolled-up parent topic will change to run from the start date of the first task to the due date of the last task.

If however you do intend the tasks to run concurrently, you can use the following formula on the parent topic to find the total durations of all the child tasks: [Total Duration]=SUM(Children.DurationDays)


Hallo Holger,

Nick has already explained that the duration is the period from the beginning to the end of the tasks.
If you want the total sum of all tasks, you can easily calculate it. see my example.


For more details write to me




thank you for the fast feedback
I chose the formula