Free Slack, also called float, is the amount of time a task can slip before it bumps into another task. It’s automatically calculated into your project when you schedule tasks, and you can use it as buffer time if needed when your schedule is at risk of being delayed.
By default and by definition, a task with zero (0) free slack is considered a critical task. If a critical task is delayed, the project finish date is also delayed.
Inspire Planner automatically calculates both Free Slack and Total Slack. Free Slack is the number of days a task can be delayed before it impacts its successor task(s). If the task does not have a successor, then it is calculated as the number of days it can be delayed before it impacts the Project Finish Date.
Total Slack is the number of days a task can be delayed before it impacts the Project Finish Date.
The Project Scheduling Mode must be set to "Automatic" for Free and Total Slack to calculate correctly.
Both Free and Total Slack columns are hidden by default in the Inspire Project UI. To add them add them to the Project UI, follow the steps outlined below: