Interactive Project Management Demonstration

Critical Path Method

Build the project network one activity at a time, then calculate the Forward Pass, Backward Pass, Total Float, Free Float, project duration, and critical path one activity at a time.

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Demonstration at a glance
Level Intermediate
Typical duration 5–10 minutes
Learning format Guided interactive simulation
Best for Project managers, planners and certification learners
Demonstration overview

Learn CPM by Building and Calculating the Network.

This demonstration uses a guided Activity-on-Node example. The network is not shown in advance. You construct it progressively, one activity at a time. Once the network is complete, every schedule calculation is revealed for one activity at a time so you can follow the logic and verify each result before moving on.

  • Build Activities A through F one at a time.
  • Reveal each activity’s Early Start and Early Finish calculation.
  • Reveal each activity’s Late Finish and Late Start calculation.
  • Calculate Total Float and Free Float for every activity individually.
  • Evaluate all six activities as critical or noncritical before revealing the complete critical path.
Guided Demonstration

Critical Path Method — Step by Step

Use the orange button to reveal exactly one new activity or one new activity calculation. Complete all activities in the current stage before the next stage unlocks.

Learning stages
Foundation Stage 1 of 8

Review the Activity Data

Current instruction
Interactive Network

Activity-on-Node Network Diagram

The network is constructed activity by activity.

Network status: Review the activity data, then begin construction.
Supporting Calculation Table

Schedule Values

The table mirrors the values revealed on the network. It does not reveal calculations before the corresponding activity has been completed in the guided stage.

Activity Predecessor(s) Duration ES EF LS LF TF FF
Experiment Mode

Change Activity Durations

After completing the guided sequence, change the activity durations and observe how the project duration, float values, and critical path respond.

Check Your Understanding

Quick Knowledge Check

CPM Quick Reference

Calculation Rules

Calculation Rule Memory Cue
Early Start Maximum EF of immediate predecessors Forward Pass → MAX
Early Finish EF = ES + Duration Move left → right
Late Finish Minimum LS of immediate successors Backward Pass → MIN
Late Start LS = LF − Duration Move right → left
Total Float TF = LS − ES = LF − EF Protect project completion
Free Float FF = Minimum successor ES − activity EF Protect successor early start
Critical Activity Total Float = 0 No schedule flexibility
Forward Pass → MAX
Backward Pass → MIN
Zero Total Float → Critical