My Settings #02: P6 Duration Unit & Date Format

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Apologies for not posting in weeks, I have been very busy at work where our 2016 offshore campaign is in full swing but I promise henceforth to come up with a post at least once every fortnight. Today's post is a continuation of my P6 settings where I explain why I develop & update schedules with duration in hours and date format with time displayed.

My schedule presentation depends on the type of schedule and thus the format of my Gantt charts are usually;

For short-term lookaheads (up to 2-week)

  • Duration unit is in hours
  • Date format has time displayed (i.e. hh:mm in the date)

For all other schedules

  • Duration unit is in days
  • Date format without time displayed (i.e. without hh:mm in the date)

The reason for the these 2 different presentations is that with the short-term lookahead schedule, the focus is on what is due in the immediate future and by showing duration in hours and displaying time with date emphasizes the lower level of detail required when looking at activities within an immediate time window. With longer term schedules, there is no real need for granularity in duration & dates hence the use of days as unit of duration and exclusion of time from dates.

While I have got the 2 options outlined above for presenting my schedules to an audience, I always develop & update my P6 schedules using the same settings; my unit of time (duration) is always in hours and my date format always has time (i.e. hh:mm) displayed.

Why I use hours as my unit of time when developing or updating schedules

If you've read Ron Winter's "The Inner Workings of Oracle/Primavera P6" which I recommended in an earlier post, Understanding How P6 Works, you would know that P6 coverts duration to seconds before it is stored in the database and when you want this duration displayed, P6 converts it from seconds to your chosen unit based on your defined conversion factors. 

Even though P6 stores duration in seconds, technically P6 lowest unit of time can be said to be hours since irrespective of your P6 calendar, 
  • 60 seconds is always equal to 1 minute
  • 60 minutes is always equal to 1 hour
Therefore, working with hours as unit of time means you do not have to worry about your activity calendars since Hours/Day is the lowest time period in a P6 calendar. Entering the activity duration in hours will ensure that your duration will always reflect an activity's duration so that if working pattern (calendar) changes in future, the activity duration remains the same as shown below for same activities 12-hr day & 24-hr calendars.

Unlike if duration is entered in days and calendar changes in future, the activity duration will change because of how P6 stores duration as shown below for same activities 12-hr day & 24-hr calendars. In reality, activity duration has not changed but activity calendar has.

Why I display time in my date format when developing or updating schedules

I first came across this problem when I switched from P3 to P6 and luckily for us, renowned Primavera P6 author, Paul E. Harris has written a very good PowerPoint presentation titled "P6 Date and Time Issue Presentation" which explain the problems with not showing time when developing or updating a P6 schedule. This presentation is available for free download from his website.


Do you use any of the settings outlined above? Always, please share your thoughts with us using the comments box below. Thanks for visiting my blog.


  1. Thanks for the wonderful article, easy to read, understand and of course quite useful.

  2. Thanks Jerome for sharing your own personal setitng complemented with excellent reference presentation from Paul E. Harris.


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