How to Show the Critical Path in P6

Show Critical Path in P6

Can’t find your Critical Path in Primavera P6? Don’t worry, it might be hiding. Here are 4 easy ways you can laser-in on your project’s Critical Path in P6.

4 Easy Ways to Show the Critical Path in P6

1. Check the Gantt Chart

By default, the P6 Gantt chart will show your project’s Critical Path activities in bright red. This makes it easy to have a quick glance at the Gantt Chart et voila!, your Critical Path stands-out like a safety vest.

Show Critical Path on the P6 Gantt Chart


Hey! It’s not working! I don’t see any red Critical Path activities on my project. What gives?

Glad you asked. 😉  Maybe your Gantt chart looks like this instead.

no Critical Path in P6 Gantt Chart

Primavera P6, by default, uses Total Float to decide if an Activity is Critical or not. Activities with a Total Float value of 0 (or less) usually show red on the Gantt. If you have no red Activities, you may have a Must Finish By date set on your project. If your project is finishing earlier than the Must Finish By deadline, then you may not have any activities with 0 or less Float values which means there are no Critical activities.

If that’s the case, tell P6 to show Critical Path by the Longest Path rather than by Total Float.

  1. Press F9, and then click the Options button.
  2. Find the setting “Define Critical Activities as”. Choose Longest Path.
  3. Reschedule your Project.
  4. Notice the Gantt chart now. You should see a red Critical Path now.

You can always read more about the Critical Path vs Longest Path.

2. Use the Critical Path / Longest Path Columns

Edit your columns and go digging for one called “Critcal” and another called “Longest Path”. Add one or both of these nifty columns to your Activity Layout to show clearly which activities are Critical.

Critical or Longest Path Column in Primavera P6


3. Turn On a Filter

Using a Filter can also be a quick and effective way to manifest your Critical Path. Click the Filters button to turn on the Critical Path filter. This will show only the Critical Activities. There’s also a filter for the Longest Path.

Critical Path Filter Primavera P6

4. Check the Schedule Log

Lastly, you can always check the P6 Schedule Log.  The Schedule Log is a log file that gets updated every time your project is scheduled. Press F9 and make sure the box labeled “Log to File” is checked on. Then, click the “View Log” button to open the Schedule Log.

Once you have the log file open in Notepad, you’ll have to scroll down to the section labeled “Exceptions”. But you should see in the log a list of your project’s Critical Activities.



What Do You Think?

Which method works best for you in Primavera P6? Do you have your own method for finding your project’s Critical Path? Drop us a line in the comments.


  1. says

    I’ve just tested the review of the Longest Path in P6 R7, and it would appear that the use of Level of Effort tasks completely renders the Longest Path calculations useless. LOE tasks and the final milestones are the only tasks which appear. Pity for those of us who use LOE tasks.

  2. Rod Ward says

    I have used Level of Effort with P6 EPPM 8.2 many times. It gives the LOE activities a duration dependant on other activities and removes te LOE activities from the critical path. However, they can be on the longest path. This makes sense to me, but I wouldn’t mind it if the LOE activities stayed off the longest path.

  3. says

    Strange – are there any lags in your LOE relationships by chance? I did some testing and I did find that my LOEs were on the Longest Path (not completely sure why). Are the tasks that your LOE is summarizing not on the Longest Path?

  4. Jorge Campos says

    Jody, good point to ensure we may have a Must Finish By date set on your project or that the project is finishing Earlier Than the Must Finish By deadline

  5. says

    Dear Mike,

    In the figure attached with item 2, we find the items marked as in the Longest Path, are not Critical. Is it possible for activities in the longest path not to be critical?

  6. says

    @Jose, yes and no. The screenshot in 2. shows which activities are Critical by the Total Float method (Critical column) and which activities are Critical by the Longest Path method (Longest Path column).

    Over here I explain that the Longest Path is a Critical Path, but not all Critical Paths are the Longest.

    What is happening is that there are 2 ways to define what’s Critical. Yes, some activities on the Longest Path may not be considered Critical by Total Float. Thus, I recommend being aware that this is the case and being aware of the Longest Path.

  7. MARIOS K says

    Dear Mike,

    Your lesson about critical path is really useful. But i have just one question. Can the Primavera programm calculate the duration of critical path or i have to do that manually. I cant find any command at P6. My definite target is to calculate the variance of Critical Path duration between the CP duration before and after levellling.

    Thanks in advance

    • PlannerTuts says

      Hi Marios,
      Put on the Critical filter, and make sure you have Grouping set to WBS. The Duration at the very top is the Duration of the Critical Path. To see the variance, you could create a baseline of your project before leveling. Assign the baseline to the project. Then, add a column to your view – “Variance – BL Project Duration”. This will be the variance after leveling.

      • MARIOS K says

        Thank you very much for your reply. I wasn’t sure about the duration while filtering the project by critical path.

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