Tool

Monte Carlo simulator

10,000 stochastic paths over your horizon using GBM-parameterized returns. Shows the full distribution of outcomes, not just the single-point estimate a deterministic projection gives you. All values shown in today's dollars (inflation-deflated).

Hypothetical simulations. Random paths generated from your assumptions using geometric Brownian motion — a simplified model. Actual markets exhibit fat tails, volatility clustering, and autocorrelation that this model understates. Outputs are impersonal analysis for educational use, not a forecast and not a recommendation.

Assumptions

Starting balance ($)

Annual contribution ($)

Horizon (years)

Years until withdrawal starts

Expected return (%)

Annual volatility (%)

Inflation (%)

Target (today's $)

Annual spend in decumulation ($)

# paths (up to 20k)

Click Run simulation to generate 10,000 paths. Takes ~2-5 seconds.