Summary Statistics
Success Rate
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Median Ending Balance
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10th Percentile
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90th Percentile
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Retirement Drawdown Calculator
Monte Carlo simulator — test how long your money lasts under thousands of market scenarios
What is a Monte Carlo Simulation?
Instead of assuming the stock market returns exactly 7% every year, this tool runs thousands of "what-if" scenarios with random (but realistic) returns. You get a clear picture of how often your money lasts -- not just the best-case.
1. Set your starting portfolio and withdrawal rate. 2. Choose a strategy. 3. Click "Run Simulation" and review your success rate.
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Start the CourseFrequently Asked Questions
How long will my retirement money last?
That depends on three variables: how much you have saved, how much you withdraw each year, and what the market does. The 4% rule (withdrawing 4% of your starting portfolio per year) has historically had a high success rate over 30-year periods. This tool runs thousands of random market scenarios to show you the probability your money lasts your chosen number of years.
What is the 4% rule in retirement?
The 4% rule is a widely-cited guideline from the 1994 Trinity Study suggesting that retirees can withdraw 4% of their starting portfolio in year one, then adjust for inflation annually, and have a high probability of not running out of money over a 30-year retirement. This tool lets you explore the 4% rule alongside other withdrawal rates and strategies.
What is a Monte Carlo simulation for retirement?
Instead of assuming steady 7% annual returns, a Monte Carlo simulation runs thousands of scenarios using random but historically-calibrated annual returns. Some scenarios have a market crash in year 2; others have strong early returns. The output is a success rate: the percentage of scenarios where your money lasted the full period.
What withdrawal rate makes money last forever?
No withdrawal rate guarantees money lasts forever, but historically, withdrawal rates at or below 3% have very high survival rates across 40+ year periods in diversified portfolios. The guardrails strategy (adjusting withdrawals when your balance drops below 80% or rises above 120% of the starting value) is one of the best approaches for longevity. Use this tool to compare strategies directly.
What is the guardrails retirement strategy?
The guardrails strategy adjusts your annual withdrawal based on your portfolio's current value. If your balance drops to 80% of the starting value, you cut withdrawals by 10%. If it rises to 120%, you can increase spending. This reduces the risk of running out of money in bad markets while still allowing you to spend more in good markets.