Actual number of days working on the task VS period of time to complete the task

New Contributor

Hi All,

You may find my question stupid, but after a long hassle, I decided to ask for help. 

Given: Say I input a new summary task for the project and say this summary task has 5 tasks. The time period for each task is 1 week (5 days) and the time gap between tasks is 3 weeks (15 days). I set the project time to be calculated in days. After all that, my summary task shows that the total amount of working time is 100 days (working + gap), instead of 25 days of actual work.

Pop-quiz: how can I set the summary task to show the actual amount of working time instead of the total time including gaps? 

Sorry if it all sounds confusing, I tried to be as specific as I could.
Thanks to everyone in advance!

P.S. I use MP 365

6 Replies
ICNARC261 --

The Duration of a summary task is calculated from the Start date of the earliest starting subtask to the Finish date of the latest finishing subtask. The Duration is calculated as the number of working days during that time period as defined by your Project calendar (set in the Project Information dialog). Think of the Duration for the summary task as the "time span" for that summary section. To see the amount of working time, assign resources to the tasks, which will populate the Work field for each subtask and for the summary task as well.

Also, there is no way to force Microsoft Project to calculate the Duration of summary tasks the way you want. Sorry, but hope this helps.
If I may add to Dale's excellent answer. One of the things that confuses many new users of Project is the difference between duration and work. As Dale noted, duration is the time span of a task. Work is the effort one or more resources perform to accomplish a task. If a single resource works full time on a task, then the duration and work will be equal.

One other thing I'd like to clarify that often is misunderstood by new users . Summary lines are NOT tasks, they are simply a summary of performance tasks under them. Summary line should have no resources assigned and no predecessors or successors.



Use a custom Duration field (say Duration1) with formula = [Duration] and under the calculation for task and group summary rows, tick the Rollup checkbox and select Sum from the dropdown.

Actual Working Days.png



Clever trick. I like it. But the formula fails if any of the tasks overlap in the summary section. But still a nice trick anyway! It would work for this user's particular situation.
Thank you very much, everyone. I guess I would just have to learn to deal with it.
You're welcome and thanks for the feedback.