Critical Path Calculator

Critical path analysis is an integral component of project management, as it determines the duration of a project, as well as the sequence of key project tasks which govern the project's completion time. With this information, the project manager can focus on getting the critical tasks completed on time, while allowing other tasks to slip their schedule if necessary, without jeopardizing the project's deadline.

This tool will determine the tasks on your project's critical path, and as a result, your project's duration. Also, for each task in the project, it will report the earliest start time and the slack, which is the amount of time the task's completion can be delayed without delaying the entire project.

How to use this tool...

To analyze your project, enter your list of project tasks, one task per line. On each line, write the task name, its duration in the time unit of your choice, and the list of tasks on which the task depends - i.e. the list of tasks that must be completed before the given task can begin. Separate each by one or more spaces or tabs. For example, if a task called "Assemble widget" takes 7 minutes to complete, but can't start until tasks "Transport parts" and "Prepare assembly machine" have completed, then you'd write:

            "Assemble widget"     7     "Transport parts"     "Prepare assembly machine"

Of course, you'd also need to define the "Transport parts" and "Prepare assembly machine" tasks on their own lines in the above example.

Want to try a demo?

Click the button below to insert a simple building construction project demo.


  • Task names must be enclosed by quotes ("") if they contain spaces or tabs - if not, quotes are optional.
  • Duration time units are generic, however the time units must be uniform for all task entries, otherwise the results will be incorrect. The start times reported in the results will be based on a project start time of 0.
  • The task list can be entered in the text box below, or uploaded as a text file in the same format. There is a 5 megabyte file size limit.
  • For more information on this topic, refer to the Wikipedia article on the critical path method.
*** Please read this important disclaimer before using this tool.

Enter task list in the box below:

...or upload the task list as a plain text file: (** 5mb max)