Monte Carlo Simulation
Predict project completion dates with confidence using probabilistic simulation. Run thousands of scenarios to understand the range of possible outcomes and identify risks before they become problems.
Quick Start
Set duration estimates on your tasks
Click on any task node and expand the "Duration Estimates" section. Enter optimistic, nominal, and pessimistic durations in days. You can also set start/due dates to auto-calculate these values.
Open the simulation dialog
Click the "Simulate" button in the top-left corner of your project canvas to open the Monte Carlo simulation dialog.
Select nodes to include
Choose which tasks to include in the simulation. By default, all tasks are selected. Enable "Auto-include dependencies" to automatically add upstream tasks.
Configure and run
Set the number of iterations (more = more accurate) and the project start date. Click "Run Simulation" to generate your probability forecast.
Interpret results
Review the P50 (most likely), P85 (safe bet), and P95 (conservative) completion dates. Check the recommendations for actionable insights.
Setting Duration Estimates
Each task needs three duration estimates for the simulation to work. These represent the range of possible completion times:
Best-case scenario. Everything goes perfectly, no blockers, experienced team. This should happen about 10% of the time.
Most likely scenario. Normal conditions, typical challenges. This is your realistic "middle ground" estimate.
Worst-case scenario. Unexpected issues, dependencies delayed, scope creep. This should happen about 10% of the time.
Pro Tip: Auto-calculate from dates
Set a Start Date and Due Date on your task, and duration estimates will be auto-calculated: Optimistic = 80%, Nominal = 100%, Pessimistic = 150% of the duration.
Understanding Results
Percentile Dates (P50, P85, P95)
50% of simulations completed by this date. Use for internal planning and team targets.
85% of simulations completed by this date. Recommended for stakeholder commitments and external deadlines.
95% of simulations completed by this date. Use for contractual deadlines or critical deliverables.
Distribution Chart
The histogram shows how completion dates are distributed across all simulation runs. A narrow, tall distribution indicates high confidence; a wide, flat distribution suggests high uncertainty.
Critical Path
The critical path shows which tasks directly impact your project timeline. Delays in these tasks will delay the entire project. Focus your attention and resources on keeping these tasks on track.
Variance (Standard Deviation)
Low uncertainty - predictable
Moderate uncertainty
High uncertainty - refine estimates
Tips & Best Practices
Be honest with estimates
Resist the temptation to be overly optimistic. Realistic estimates lead to accurate forecasts.
Break down large tasks
Tasks over 2 weeks are hard to estimate. Split them into smaller, more predictable work items.
Use historical data
Look at similar past tasks to inform your estimates. Track actuals to improve future predictions.
Re-run regularly
As tasks complete or estimates change, re-run the simulation to get updated forecasts.
Communicate P85, not P50
When setting external deadlines, use the P85 date. Save P50 for internal stretch goals.
Focus on critical path
Invest extra attention in tasks on the critical path - they control your timeline.