Total Float vs Free Float
Two very different measures of “spare time.”
What it is
Total float is how long an activity can slip without delaying project completion; free float is how long it can slip without delaying its immediate successor.
Why it matters
Float ownership and consumption sit at the heart of delay analysis. Confuse the two and you mis-read how much room actually exists.
In practice
- Total float measures against the project end date; free float against the next activity.
- Negative total float means the network cannot meet a constrained date — read it as a warning, not a number to bank.
- An activity can have plenty of total float yet zero free float.
- Float is a calculated network property, not a promise — it moves as logic and progress change.
Watch for
- Treating total float as “spare time we can plan to consume” without asking who owns it.
- Constraints producing misleading, often negative, float.
- Ignoring free float when sequencing shared resources.