← Back Retirement · Risk

Monte Carlo Retirement Simulator

The 4% rule assumes average returns every year. Markets don't work that way. This runs 1,000 simulations of your retirement across random market sequences — showing your real probability of your money lasting the full retirement.

Your retirement scenario

Portfolio at retirement

Annual withdrawal

Retirement length (years)

Simulations to run

Market assumptions

Mean annual return % 7.0%

Std deviation % 15.0%

Inflation % pa 3.0%

Additional income (pension etc)

S&P 500 long-run mean ~10% nominal / ~7% real. Standard deviation ~15–17%. Bonds: ~4–5% mean, ~7% std dev. A 60/40 portfolio: ~7% mean, ~12% std dev.

Methodology: Each simulation draws annual returns from a normal distribution with specified mean and standard deviation — consistent with methodology used in Bengen (1994) and the Trinity Study (1998). Normal distribution does not capture fat tails or autocorrelation in real markets — results are indicative, not predictive. Historical S&P 500 data: mean ~10% nominal, std dev ~15–17% (1926–2024, S&P SPIVA). This is not financial advice. Consult a financial planner for personalised retirement modelling.