I have an existing project file (.mpp file). I realized that duration of all tasks is one day longer comparing to my estimation. For example, a task with duration 2 days starting at 3.6.2019 is scheduled to finish at 5.6.2019. After checking resource usage I realized that Project schedules only 7 hours for the first day of the task (3.6.2019). For the second day (4.6.2019) Project schedules 8 hours and the remaining one hour schedules for the third day (5.6.2019). This applies for all tasks within the project - work for the starting day of the task is always scheduled for 7 hours only. All tasks use fixed duration type, and all are automatically scheduled. Standard calendar with 8 working hours per day is used. What is the reason that Project schedules only 7 hours for first day of every task?

Update: I see that Project schedules the first day from 9:00 to 17:00, but all other days schedules from 8:00 to 17:00. Default start time of project calendar is set to 9:00 and default end time of project calendar is set to 18:00.

  • What is your Start date (including time) in the Project Information dialog? Newer users often modify calendars without touching this constraint. The common result is a truncated first day, with cascading impacts on later tasks.
    – Tom Boyle
    Aug 9, 2019 at 14:08
  • Start day of the project is 8.11.2018. I cannot see information about time in the Project information dialog, where can I find it?
    – Roman
    Aug 13, 2019 at 8:02
  • First choose a date format that shows time of day (File|Options|General|Project view|Date format:). Then go back to Project Information and observe the time of day on the Start date. Make sure that it is aligned with your project calendar.
    – Tom Boyle
    Aug 13, 2019 at 13:43
  • Thank you very much! I observed that starting time in Project information dialog was set to 9:00, while starting time of Standard calendar (which is used for the project) was set to 8:00. After changing the starting time in Project information dialog to 8:00 the scheduling works as I expect.
    – Roman
    Aug 14, 2019 at 9:05
  • There is just one issue: After adding Actual Start date for any task, the Project sets starting time for the task to 9:00. Similarly, after adding Actual Finish date, the project sets finishing time for the task to 18:00 (standard calendar uses 17:00). I am able to manually edit the starting/finishing time of the task, but it is not very comfortable. What else can be wrong?
    – Roman
    Aug 14, 2019 at 9:08

1 Answer 1


After modifying the calendar for a particular project, it is important to:

  1. Ensure that the time of day that is included in the "Start date" of the Project Information dialog matches the intended work time constraints of the calendar. (Otherwise, the first project day can be truncated, with cascading impacts.)
  2. Ensure that the default Calendar options for the project are aligned with the intended work time constraints of the calendar. E.g. Default start time, default end time, hours per day, etc.
  • It works! Thank you!
    – Roman
    Aug 15, 2019 at 5:04

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