
In the graphic above, which is the system default, a Day is 8 Hours, a Week is 40 Hours, a Month is 172 Hours and a Year is 2000 Hours. It is used to enter the number of hours for each Time Period. There is a Time Periods button that displays the same set of four boxes for each Calendar. When this option is not selected, the definition of a Primavera P6 Day is the same throughout the database.

This means the value of a Primavera P6 Day is determined by each P6 Calendar. This is done by selecting the Use assigned calendar to specify the number of work hours for each time period option as shown. The following screenshot shows this P6 system uses the value of Time Periods set against the Calendar in use. Primavera P6 can be set up so everyone uses exactly the same definition for each Time Period or they use one assigned to the Calendar in use at the time. The short answer is a Primavera P6 Day is as long as it has been configured to be. This post looks at how Primavera P6 achieves this and just what a Primavera P6 day actually is. The same goes for a Week, a Month and even a Year. When it comes to project scheduling we need the length of a Day to be consistent. The clocks move backwards again at the end of British Summertime and the day has 25 hours in it. On the day the clocks go forward, such as the start of British Summertime, it ends up with just 23 hours in it. Most days for most people have 24 hours in them, but not every day has 24 hours in it. There are 60 seconds in every Minute and 60 minutes in every Hour, but how many hours in each Primavera P6 Day?

WBS Guidelines for Government Acquisition Programs (MIL-STD 881D).
