What is slack in the schedule?

Slack in the schedule is the buffer time that can be used to complete a task without shifting the overall project deadline.

In simpler terms, it is the difference between the earliest and latest start or finish times of a task without disrupting the schedule.

For example, if a task can start anytime between the 1st and 3rd and finish by the 5th without delaying subsequent tasks, then the slack is these 2 days of buffer.

Slack helps managers flexibly manage resources and respond to delays without affecting the final project deadline.