What is the difference between total float and free float?

What the slip would delay. Total float is how long an activity can be delayed from its early start before it pushes the project completion date; it is a property of the whole path the activity sits on, so the float is shared among the activities on that path, and using it up on one activity reduces what is left for the others. Free float is how long an activity can be delayed without delaying the early start of its immediate successor; it belongs to that single activity and does not touch anyone else. An activity can have total float but zero free float, which means it has room against the project end but none against the next activity in line. Total float is the number schedulers watch for criticality; free float tells you how much you can move one activity without disturbing its neighbor.

What does negative float mean?

That the schedule is already behind against a constraint, before the work even happens. Negative float appears when a deadline constraint, such as a contractual milestone or a required finish date, is earlier than the dates the logic actually produces. The scheduling software reports the shortfall as negative float: minus five days of float means the current plan finishes five days later than the constraint allows. Negative float is a signal that the plan does not work as drawn and needs compression, resequencing, or a revised date, not a number to ignore. It is common right after a milestone is imposed on a schedule that was not built to meet it.

Who owns the float in a construction schedule?

It depends on the contract, and it is worth settling before a dispute. Float is a shared resource: when an activity has slack, either party could in principle consume it, the contractor by sequencing work differently or the owner by taking longer on a review or a decision. Older practice often treated float as belonging to whoever used it first, which rewards consuming it early. Many modern contracts instead say float belongs to the project, meaning neither party can treat it as a private buffer, and an owner-caused delay that only eats float may not entitle the contractor to a time extension until the float is gone. Because the answer drives whether a delay is compensable, the float-ownership clause is one to read at the start of the job, not during a claim.

Construction Glossary · Scheduling

Total & FreeFloat

Float is the room an activity has to move before something breaks. Total float protects the finish date; free float protects the next activity in line.

Definition

Total float is the number of days an activity can slip from its early start without delaying the project completion date. Free float is the number of days it can slip without delaying the early start of any successor. Total float is shared along a path; free float belongs to a single activity. An activity with zero total float is on the critical path, and negative total float means the schedule is already late against a constraint.

How far it can slide, and before what breaks

This activity can slide six days before the project finish moves, its total float. But after only three days it would push its successor, so its free float is three. The first number protects the end date; the second protects the neighbor.

Total, free, and negative

Three float readings a scheduler acts on differently. Zero total float is the critical path; negative float is a plan that does not work yet.

Reading	Means	What to do
Total float > 0	Slack before the finish moves	Monitor; it is shared along the path
Total float = 0	On the critical path	Protect it — any slip moves the finish
Free float > 0	Slack before the successor moves	You can shift this activity alone
Negative float	Late against a constraint already	Compress, resequence, or revise the date

Zero total float is the critical path; eating an owner’s delay into float is central to compensable delay.

How POD reads float

POD reads each activity’s total float from the Primavera P6 or Microsoft Project schedule you import, so the activities with no slack, the critical ones, are visible alongside the field data rather than buried in a scheduling file few people open. When a daily report shows an activity slipping, its float tells you immediately whether that slip threatens the finish or is absorbed. POD reads the float the scheduling tool calculated; it does not run the forward and backward pass itself or decide how float is owned under your contract. It surfaces the number so the slip can be judged the moment it is reported.

Critical path method guide

Frequently asked questions

Float is computed; variance is measured

Float comes from the schedule logic itself, the forward and backward pass over the current network. What you measure against the frozen baseline is variance: how far the plan has drifted. That is the baseline's job.

Baseline Schedule Back to the Glossary