1) Total float refers to the amount of time an activity can be delayed without delaying the project's estimated completion time. It assumes all preceding activities finish as early as possible and all succeeding activities start as late as possible. Total float can be calculated using the late start and early start or late finish and early finish of an activity. 2) Free float is the amount of time an activity can be delayed without impacting the project's estimated completion time or delaying succeeding activities. It is calculated using the early finish of an activity and the minimum early start of its successor activities. 3) Interfering float allows delaying an activity without impacting the project's completion, but it could delay one or more

1. 1) Total Float.
Total float is the amount of time that an activity can be delayed without delaying the project's
estimated completion time.
Total float assumes that.
All preceding activities are finished as early as possible.
All succeeding activities are started as late as possible.
Total float for an activity can be determined either:
Total float activity n = Late start activity n " Early start activity n.
Total float activity n = Late finish activity n " Early finish activity n.
Where n denotes the nth activity.
Both the equation will yield the same answer.
2) Free float.
Free float is the duration of time, that an activity can be delayed without delaying the project's
estimated completion time and without delaying the start of any succeeding activity.
Free float is the property of an activity, not a network path. The Free float can be determined
by:
Free float n = Minimum early start of all successor activities " Early finish n.
Where n denotes the nth activity.
3) Interfering float.
The Interfering float is the time available to delay an activity without delaying the project's
estimated completion time, but delaying an activity into interfering float will delay the start of
one or more following non-critical activities.
Interfering float n = late finish n " Smallest early start of the succeeding activity.
The aggregate of free float and interfering float is equal to the total float.