Calculating task time RRS feed

  • Question

  • Hi all,

    I am new at this forum so I hop this is the correct place to ask this question.

    For a project, I have 2 deadlines (A and B). In between these 2 deadlines there are 3 tasks that take place (X, Y and Z). I want MS Project to calculate the time for tasks X, Y and Z based on the total time between A and B. In this example, X is 50% of the time, Y 30% and Z 20%. When the time between A and B equals 20 days, X should take 10 days, Y 6 days and Z 4 days.

    My question: Is is possible for MS Project 2010 to use some formula to calculate the duration times of tasks X, Y and Z?

    Thank you for helping me!

    Cheers, Koen

    Wednesday, April 1, 2015 10:13 AM

All replies

  • Hi Koen,

    Unfortunately the duration cannot be calculated by a formula. You eventually have duration custom fields but anyway formulas can only refer to the row they are attached to, not to another row. Either you do some custom VBA code, or you set the duration manually.

    Hope this helps,

    Guillaume Rouyre, MBA, MVP, P-Seller |

    Wednesday, April 1, 2015 10:50 AM
  • Hi Koen,

    if you know a little bit of VBA you can do a Macro to calculate the durations dynamically.


    Wednesday, April 1, 2015 1:27 PM
  • I would also use a Task Custom Field to store the percentage to calculate for a given task, as you will likely need to add other tasks. You could also use a second task custom field as a metadata tag field. That way, you can denote which is A and which is B without having to make the Task Name significant.

    I did something like this once for a client setup project. The durations where driven by five data elements, entered into a custom field. Using the task custom fields ensures you don't have to change your macro the first time requirements change.

    Treb Gatte, Project MVP | Blog | Twitter | YouTube Channel

    Wednesday, April 1, 2015 7:00 PM
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    If you think this was valuable please mark my reply as a valid answer. Thanks. Kind Regards, João Frederico Neto --

    Monday, November 23, 2015 4:52 PM