Carlo
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    Getting Started

    Build Monte Carlo models using a visual canvas. Define distributions, reference variables in formulas, and run thousands of scenarios—no coding required.

    Overview

    Monte Carlo simulation runs thousands of random samples to reveal the full range of possible outcomes. Instead of a single estimate like "the project costs $100,000," you see a distribution: there's a 90% probability the cost falls between $85,000 and $120,000.

    Block Palette

    The palette in the top-left corner contains all block types. Click to add at center, or drag to place anywhere on the canvas.

    Core blocks

    • Variable: Model uncertain inputs with probability distributions.
    • Constant: Hold fixed values.
    • Formula: Combine inputs with mathematical expressions.
    • Output: Collect results to display in the results panel.

    Advanced blocks

    • Data: Import CSV/Excel data and sample from columns.
    • Copula: Model correlated variables.
    • Time Series: Values that evolve over time.

    Workflow

    1. Add blocks

    Start with Variable blocks for uncertain inputs, Formula blocks for calculations, and Output blocks to collect results.

    2. Reference variables

    In Formula and Time Series blocks, type the variable name of another block to reference it. Connections appear automatically based on these references—no manual wiring needed.

    3. Run the simulation

    Click Run to execute thousands of iterations. Each iteration samples from your distributions and computes the outcomes.

    4. Analyze results

    View histograms, statistics, sensitivity analysis, and probability calculations in the Results tab.

    Tips

    Start with examples. Browse existing models to see working examples. When you edit an example, Carlo automatically creates your own copy.

    • Choose distributions wisely. Use Normal for symmetric data, Triangular for expert estimates (min, likely, max), Log-Normal for positive-only values, and Beta for probabilities between 0 and 1.
    • Check sensitivity analysis. The tornado chart shows which inputs have the greatest impact on your outputs. Focus refinement on high-impact variables.
    • Use keyboard shortcuts. Quick-add with V C F O N. Hold Space to pan.
    • Watch complexity limits. Carlo caps simulations at 5M operations. The run dialog shows your operation count.
    • Validate before running. Open the debug panel to catch unconnected blocks, circular dependencies, or missing inputs.