Float Calculation

Float, also known as slack, refers to the amount of time that a task can be delayed without causing a delay to subsequent tasks or the overall project completion date. In the context of the Critical Path Method (CPM), calculating float is crucial for understanding scheduling flexibility and identifying critical activities. There are two main types of float: 1. **Total Float**: The difference between the earliest and latest start times (or finish times) of an activity. It indicates how much an activity can be delayed without affecting the project's end date. 2. **Free Float**: The amount of time an activity can be delayed without delaying the earliest start of any subsequent activities. To calculate float, a project manager performs forward and backward pass analyses through the project schedule network diagram. The forward pass determines the earliest start and finish times, while the backward pass calculates the latest start and finish times. The formulas are: - **Total Float** = Late Start - Early Start or Late Finish - Early Finish - **Free Float** = Earliest Early Start of successor activities - Early Finish of the current activity By understanding float, project managers can identify which activities have scheduling flexibility and which are on the critical path with zero float. This insight helps in resource leveling, risk management, and optimizing the project schedule to prevent delays.