I would like to compute the real finish date, I mean :

If Start date is 01/01/2015. and the Duration is 7 days , the real finish date is supposed to be 07/01/2015 (or at least 08/01/2015).

Please how to do that under Microsoft Project 2013 ??

Do I use a formula in custom field ? for instance :

  • 1
    Are you working 7 days a week? If so, you need to change your working calendar to reflect working 7 days per week. So, why would the "real finish date" be seven calendar days after if you aren't working 7 days per week? A word of caution about elapsed duration - as Rachel notes. It works fine as long as you do not assign resources to the tasks. An elapsed day is 24 hours. If you created a task with a duration of 2ed - your resources would be scheduled to work 48 hours and both your work estimate and cost estimate will be inflated.
    – JulieS
    Aug 1, 2015 at 0:38
  • I have not assigned ressources, but this is a good point to take in consideration. I will test that and get back to you
    – user17770
    Aug 1, 2015 at 7:05

2 Answers 2


Use elapsed days for durations that do not depend on working time. Enter the duration as "7ed".

Using elapsed durations bypasses all calendars (project, task, resource) and task type when calculating the finish date. They are typically used when the task duration is based on something physical (eg curing time) or something contractual (eg x needs to happen 30 days before/after some event). The latter is usually seen in lag durations.

To make a duration elapsed, put the letter e before the duration unit. This works for all units but is mostly used with days.

Examples: "7ed", "5 edays"

  • interesting .... that worked . can you detail more, with a reference please so that I can be sure it is the right solution , and set your answer as the right one.
    – user17770
    Jul 28, 2015 at 13:07

I'm guessing the problem you have is that duration defaults to work days (assumes 5 work days per week) and you are concerned about calendar days. There are a couple of ways around this:

  • Don't use days. Use weeks or months (so type in "1 week" under duration). This is my preferred option.
  • Change default duration unit to calendar days. You should be able to this this as follows:
    • Go to the Tools menu, select Options and then select the Calendar tab
    • Reset the default number of days per month to 30 or 31.

Obviously the second option isn't perfect 100% of the time, but if your time-frames for your tasks is typically less than one week it should be good enough for estimation purposes.

  • thank you for your solution, but i checked it does not work ! 1 I already use months, 2 Days per month is already set to 30 !
    – user17770
    Jul 28, 2015 at 12:49
  • Just to clarify - it doesn't matter how you express the duration (minutes, hours, days, weeks etc) it will also count working time as defined in the calendar.
    – JulieS
    Aug 1, 2015 at 0:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.