Total float is the amount of time that an activity can be delayed from its earliest start date without delaying the project completion date or violating a schedule constraint. It is calculated as the difference between the latest allowable end time and the earliest allowable end time of a schedule activity.
For instance, if an activity can be delayed by a certain number of days without affecting the overall project timeline, that delay period represents the total float. This concept is essential in project scheduling because it allows flexibility in managing activities without compromising the project's final deadline.