Critical Path Method Calculator
Estimate project duration using Critical Path Method (CPM). Calculate critical path length, total float, and schedule compression potential.
Inputs
Results
Total Project Duration
60 days
Critical Path Length
60 days
How to Use This Calculator
- Enter Total Activities, Avg Activity Duration, and Parallel Paths.
- Set Critical Activities.
- Review Total Project Duration (days) and Critical Path Length (days).
- Use Total Float (days) and Avg Float per Activity (days) to inform your decision.
- Use the chart to visualize the results and explore different scenarios by adjusting inputs.
How the result changes with Avg Activity Duration
| Avg Activity Duration | Total Project Duration | Critical Path Length |
|---|---|---|
| 6.9 | 82.8 days | 82.8 days |
| 22 | 264 days | 264 days |
| 39 | 468 days | 468 days |
| 54 | 648 days | 648 days |
What each input means
- Total Activities
- Total number of activities or tasks in the project schedule.
- Avg Activity Duration
- Average duration per activity in working days.
- Parallel Paths
- Number of work streams that can proceed simultaneously.
- Critical Activities
- Number of activities on the longest (critical) path with zero float.
What each result means
- Total Project Duration
- Estimated project duration in working days.
- Critical Path Length
- Duration of the critical path (zero float activities).
- Total Float
- Available slack before non-critical activities delay the project.
- Avg Float per Activity
- Average slack available for non-critical activities.
- Crash Potential
- Estimated days that could be saved by crashing critical activities (~15%).
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersTotal Activities = 25, Avg Activity Duration = 5, Parallel Paths = 4, Critical Activities = 12 = 4 input(s) provided
- Calculate Total Project DurationTotal Project Duration60 = 60
- Calculate Critical Path LengthCritical Path Length60 = 60
- Calculate Total FloatTotal Float0 = 0
- Calculate Avg Float per ActivityAvg Float per Activity0 = 0
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.
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