Critical Path Method Calculator

About this calculator

The critical path method builds a network of project activities with their durations and dependencies (predecessors), then runs a forward pass to find each activity's earliest possible start and finish, and a backward pass to find its latest allowable start and finish without delaying the project. Activities where earliest and latest times coincide have zero slack — they form the critical path, the longest sequence through the network, which sets the minimum possible project duration.

Project managers, especially in construction, engineering, and software delivery, use CPM to identify which tasks can't slip without delaying the whole project, to focus monitoring and resources on those critical activities, and to see exactly how much slack (float) exists in the non-critical ones.