Monte Carlo Forensic Engine
"Analyze the mathematical probability of your retirement plan succeeding across 1,000+ different market scenarios."
Will Your Money Last?
Traditional engines use a fixed 'average' return, but real markets go up and down. A Monte Carlo simulation tests your plan against 1,000+ random market paths—including crashes and booms—to see how often you 'run out of money'.
📝 How to use
- 1Enter your starting retirement savings and planned annual spending.
- 2Set your expected average return and how much the market swings (volatility).
- 3Run the simulation to see your "Success Rate"—the percentage of scenarios where you stay solvent.
🎯 Real-World Scenarios
The "Sequence of Returns" Risk
A market crash early in retirement is much more dangerous than one later. This simulator accounts for that timing luck.
Inflation Protection
We assume your spending increases by 2% annually to keep up with the rising cost of living.
Frequently Asked Questions
What is a "Success Rate"?▼
Why does the result change every time?▼
What is a "Sequence of Returns" risk?▼
Simulation Inputs
Simulation Results
Portfolio Projection Range
What This Calculator Solves
This engine moves beyond 'average' returns to show you the reality of market volatility. By running 1,000+ random scenarios, it helps you understand if your retirement plan is 'robust' enough to survive a market crash early in your retirement, or if you need to adjust your spending or savings goals.
The Danger of 'Sequence of Returns' Risk
Most people plan retirement based on an average annual return (e.g., 6%). However, the timing of those returns matters much more than the average itself. This is known as Sequence of Returns Risk (SORR).
If the stock market crashes by 30% in your first year of retirement while you are withdrawing money, your portfolio is 'cannibalized.' Effectively, you are forced to sell stocks at their lowest prices to pay for groceries, leaving fewer shares to bounce back when the market eventually recovers.
The 'Luck' Factor: Two retirees with identical savings and identical 30-year average returns can have completely different outcomes. The one who experiences a 'Bull Market' in their first decade will likely end up with millions; the one who hits a 'Bear Market' early may run out of money in 15 years. Our Monte Carlo tool explicitly models this 'luck' to ensure your plan is crash-proof.
Methodology & Data Sources
Our engine uses a 'Geometric Brownian Motion' model to simulate market paths. We use a standard deviation (volatility) of 12% and a mean return of 6%, adjusted for a 2% inflation rate. Every time you click 'Run', 1,000 unique 40-year paths are generated to analyze the statistical probability of success.
* Calculations are for educational purposes only.