Float is time — time you can afford to lose before something bigger breaks. The difference between total and free float is what breaks: one moves the whole project finish; the other only delays the next activity in the chain. They're both important, and they answer different questions.
Total float: days until you move the finish date
Total float is the amount of time an activity can slip before it delays the project completion date. It belongs to the path, not the activity — every activity on the same chain shares the same total float pool. Use one day of it on any activity, and every other activity on that chain loses a day too.
This is why the critical path has zero total float. There's no pool left. Every day of slip on the critical path moves the finish 1:1.
Free float: days until you delay your successor
Free float is simpler and more immediate: how long can this activity slip before it delays the next activity in the chain? It belongs to the activity, not the path. If Activity C has five days of free float, it can slip five days without touching anything else — its successors start on time.
Free float is always ≤ total float. If an activity has free float, it has at least as much total float. If it has no free float, it may still have total float — but using any of it will push back the next activity in line.
Use total float to assess project-level risk. Use free float to plan daily sequencing and judge whether a single activity can be rescheduled without domino effects.
Why it matters for delay claims
When a delay claim goes to adjudication, the respondent will often argue that the delayed activity had float — so the delay didn't move the finish. The question is which float. If the activity only had total float, and other activities on the same chain had already consumed part of it before the delay event, the cushion may have been zero by the time the event occurred.
Showing total float at the time of the event — not at baseline — is what separates a defensible claim from a defeated one.
OPTEAM tracks float erosion over time, so you can show that an activity's cushion had shrunk from 8 days at baseline to 0 days by the week of the delay event — the history that makes the claim stick.
How P6 stores and displays both
Primavera P6 calculates both types on every schedule update. Total float is stored on the activity as "Total Float"; free float appears as "Free Float". The default activity columns rarely show free float — you have to add it manually — which is one reason it's so often overlooked until a claim surfaces.
OPTEAM exposes both alongside float erosion trends, flagging when a near-critical chain's buffer is running down so you catch the risk before it becomes a claim.
- Total float measures days until the project finish moves; free float measures days until the next activity is blocked.
- Total float belongs to the path — every activity on it shares the same pool.
- Free float belongs to the activity — it can slip that much without touching anyone else.
- For claims, show float at the time of the event, not at baseline, to prove the cushion was gone.
See float erosion on your live schedule.
OPTEAM tracks total and free float on every update and flags when near-critical chains are running down.