Total Float is the amount of time that a schedule activity can be delayed or extended from its early start date without delaying the project finish date or violating a schedule constraint.
It is used to measure schedule flexibility, determine which activities are on the critical path, and assess how much buffer time exists before an activity impacts project completion. Activities with zero total float are considered critical.
Key Characteristics
- Time-Based Flexibility – Indicates how much delay can occur without affecting the final deadline
- Calculated Using Network Logic – Derived from forward and backward pass in the schedule model
- Used in Critical Path Analysis – Helps identify non-critical versus critical tasks
- Impacts Risk and Planning Decisions – Guides where to focus monitoring and buffers
Example Scenarios
- An activity with 3 days of total float can be delayed up to 3 days without impacting the project
- Identifying which non-critical path activities can absorb resource reallocation
- Using total float values to prioritize which delays require escalation
Formula
Where:
- LS = Late Start
- ES = Early Start
- LF = Late Finish
- EF = Early Finish
Role in Schedule Management
- Supports Schedule Optimization – Reveals flexibility and buffer opportunities
- Guides Resource Leveling – Helps adjust workloads without affecting deadlines
- Enables Impact Analysis – Clarifies which tasks pose risk to overall schedule
- Improves Visibility – Assists in stakeholder communication around timeline risks
See also: Free Float, Critical Path, Near-Critical Activity, Near-Critical Path, Schedule Network Analysis.