Calculator
PERT Calculator
Estimate project activity duration using optimistic, most likely, and pessimistic estimates.
Calculator
Estimate uncertain activity durations
Use this tool during early planning, schedule development, risk discussions, and estimation workshops when a single-point estimate is too weak.
PERT result
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Standard deviation—
Variance—
Indicative planning range—
The highlighted marker shows the calculated expected duration. The shaded band shows the indicative planning range.
Recommended actions
- Review assumptions behind each estimate.
- Confirm whether the pessimistic estimate reflects real delivery risks.
- Discuss mitigation actions for uncertainty.
- Update the schedule with a realistic planning duration.
- Consider contingency for high-uncertainty activities.