Project Float and Slack: How to Calculate Free Float and Total Float

Quick answer

Float (slack) is how long a task can slip without delaying the project — free float vs total float; the critical path has zero float, which is why it’s critical.

Total float

How much a task can slip without delaying the project — the whole buffer that path has.

Free float

How much a task can slip without delaying the next task — the local buffer.

Critical path = zero float

The longest path has no slack — every day there is a day to the finish.

Using float

Buffer where it matters — float is the schedule’s shock absorber; know where it lives.

Bottom line

Float (slack) is how long a task can slip without delaying the project — free float vs total float; the critical path has zero float, which is why it’s critical.

If this post was helpful, you might also enjoy Project Budget Management: Complete Guide and Task Management vs Project Management.