Critical path

Find what is truly unmovable in your schedule.

Project duration
— weeks
Critical tasks
—

What you are looking at

Each node shows four numbers: duration, Early Start, Early Finish and float. Nodes with float equal to zero form the critical path — highlighted in purple. The forward pass calculates the earliest each task can start and finish. The backward pass calculates the latest. Float is the gap between them. Drag the delay sliders to slip any task and watch the end date and critical path recalculate live.

What most PMs miss

The critical path changes during the project. A task that had float in week one may have none by week six because other delays consumed the buffer. PMs who calculate the critical path once at kickoff and never revisit it are managing a map that no longer matches the terrain. Recalculate it weekly during execution.

The expert tip

Try slipping a non-critical task in the simulator until it absorbs all its float. Watch it join the critical path. That is the key insight: float is not free time, it is a budget. When a sponsor asks you to accelerate, show them this chart and point to exactly which tasks need crashing — that turns schedule negotiation from opinion into data.