Monte Carlo Concept Simulator
See how repeated random sampling converts uncertain cost estimates and a discrete risk event into a distribution of possible project outcomes, then interpret mean cost, P50, P80, P90, contingency and sensitivity.
Replace a Single-Point Estimate with a Distribution of Possible Outcomes.
Monte Carlo simulation repeatedly samples uncertain inputs and recalculates the project outcome. This concept simulator uses four triangular project-cost estimates and one discrete cost-risk event. Thousands of trials create a distribution that can be interpreted through percentiles and confidence levels.
- Review Minimum / Most Likely / Maximum cost ranges.
- Add a discrete risk event with probability and cost consequence.
- Run one trial and see each sampled value.
- Repeat thousands of times and build a histogram.
- Read P50, P80 and P90 confidence levels.
- Translate P80 into illustrative contingency above the deterministic baseline.
- Review which inputs drive the most variation.
Monte Carlo Concept Simulator — Step by Step
Complete each locked stage before the next unlocks. Every guided action changes the simulation pane.
Review the Uncertain Cost Inputs
Inputs, Trials, Distribution and Confidence
Uncertain cost ranges are introduced one input at a time.
Focus Mode opens the guided workbench as a dedicated learning overlay while keeping the current learning stage and simulation dashboard together. Dashboard Full Screen expands only the simulation dashboard. Exiting Dashboard Full Screen returns to Focus Mode when Focus Mode is active. Zoom affects only the simulation pane.
Simulation Inputs
The table mirrors the guided sequence.
| Input | Distribution | Minimum | Most Likely | Maximum | Discrete Risk |
|---|
Change Uncertainty and Re-run the Simulation
Experiment Mode is isolated from the guided example. Adjust construction uncertainty, discrete-risk probability, confidence target and number of trials.
Quick Knowledge Check
Core Concepts and Interpretation
| Concept | Meaning | Interpretation |
|---|---|---|
| Input Distribution | Represents uncertainty rather than one fixed value | This example uses triangular Minimum / Most Likely / Maximum cost distributions. |
| Iteration / Trial | One random sample from every uncertain input | One trial is one possible future—not the forecast. |
| Monte Carlo Simulation | Repeat the trial many times | The outcomes approximate the distribution implied by the input assumptions. |
| P50 / P80 / P90 | 50th / 80th / 90th percentiles | Approximately that percentage of simulated outcomes are at or below the percentile value. |
| Contingency | Selected percentile cost − deterministic baseline | The confidence target should reflect governance and risk appetite. |
| Sensitivity | Relative association between uncertain inputs and output | Highlights which assumptions drive the most simulated variation. |
Define realistic uncertainty ranges and discrete risks, run enough trials for stable results, interpret P50/P80/P90 as percentiles rather than guarantees, and use sensitivity analysis to identify which assumptions most strongly drive the simulated outcome range.