I am using a 5 working days & 8 hours standard calendar. My task is 30 days . I have selected a start date on Monday and end date on Friday (30th work day) but the durationn reflects as 40 days instead of 30 days? How can I ensure that the duration reflects the correct work days for the task?

  • Please provide more information such as the exact dates, list any constraints, if resources assigned, etc. Attaching a screen shot might help as well. Also, what happens if you try this same start date and duration in a new schedule with just this one task? Commented Dec 10, 2018 at 17:48

3 Answers 3


Hmmm - a very quick google search gave this: https://blog.epmainc.com/more-you-want-know-about-duration-everything-you-need-know/:

When you enter a Duration value for a task in Microsoft Project, the software always calculates the schedule of the task in working days. ... For example, an elapsed Duration value of 20 days means 20 calendar days, including weekends and company holidays

So in practice, the 10 additional days are weekends.


You should not be selecting start and end dates. Select the start date and duration, let project calculate the end date. Even better, don't select the start date and use predecessors to drive the date, just noting the duration.

  • 1
    This is not really what he is asking @rapscalli.
    – sonstabo
    Commented Mar 4, 2020 at 13:44
  • I am trying to advise best practice when scheduling. You should not be entering start date, end date and duration into Microsoft Project.
    – rapscalli
    Commented Mar 5, 2020 at 17:41
  • You are frame challenging the question. In pm.se, as in any other community, this needs to be done with care otherwise you'll end up attracting a lot of downvotes.
    – Tiago Cardoso
    Commented Jul 28, 2021 at 8:00
  • I would appreciate advise on how to respond to a such a question when somebody asks how to do something using a method that is itself causing the problems experienced. If I were working with a colleague and I saw them entering start and end dates I would explain the best practice in entering task information, and entering start and end dates is far from best practice. I have implemented Project Online with Microsoft Gold partners in large portfolios and they have all been consistent on this point.
    – rapscalli
    Commented Nov 4, 2021 at 8:53
  • PS - Surely the answer to the question "How can I ensure that the duration reflects the correct work days for the task" is to enter the start date and expected duration? And is pointing this out really 'frame challenging'?
    – rapscalli
    Commented Nov 4, 2021 at 8:57

Stop using MS Project - It is anti-Agile!

If you work for an organisation that wants to be Agile yet insists on MS Project plans, consider getting another job; trying to mix the 2 is both a waste of your time and theirs.


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