Monte Carlo Retirement Simulator

Run Your Free Monte Carlo Retirement Simulation Now

Our free Monte Carlo Retirement Simulator runs 1,000 market scenarios in seconds. See if your savings hold up — and exactly how much you need.

$1,000,000
$100K$10.00M
$40,000
$10K$500K
30 years
10 years50 years
60%
0% (All Bonds)100% (All Stocks)
Quick Safe Withdrawal Rates:
Success Rate
92.4%
Based on 1,000 randomized market paths.
10th Percentile
$62K
Worst 10% of outcomes
Median Outcome
$1.18M
Middle of all outcomes
90th Percentile
$3.85M
Best 10% of outcomes
Portfolio Value Over Time
Shaded bands depict the trajectory range across simulated market cycles
90th Percentile Median (50th) 10th Percentile

Frequently Asked Questions

Plug in your portfolio, withdrawal rate, and timeline. Our Monte Carlo Retirement Simulator shows your real odds of financial independence — free.

Q1. What is a Monte Carlo Retirement Simulator?

A: A Monte Carlo Retirement Simulator runs hundreds or thousands of randomized market scenarios to estimate how likely your portfolio is to last through retirement. Instead of assuming a fixed return, it models real-world volatility — giving you a probability of success, not just a single projection.

Q2. How many simulations does this tool run, and why does that number matter?

A: This simulator runs 1,000 randomized market paths per calculation. More simulations = more statistically reliable results. With 1,000 runs, the success rate percentage is stable and actionable — not a lucky outlier.

Q3. What does the "success rate" actually mean?

A: It's the percentage of simulated scenarios where your portfolio didn't hit zero before your retirement ended. A 92.5% success rate means 925 out of 1,000 simulated market paths left you with money remaining. Most financial planners target 85–95%.

Q4. How does stock allocation change my retirement success rate?

A: Higher stock allocation increases both upside potential and short-term volatility. In most Monte Carlo models, a 60–80% stock allocation produces the best long-term survival rates for 30-year retirements. Going 100% bonds often hurts longevity due to inflation erosion.

Q5. Is the 4% rule still valid for retirement planning?

A: The 4% rule (Trinity Study) holds up reasonably well for 30-year retirements with a balanced portfolio — but it was modeled on historical U.S. data. This simulator lets you test 3%, 3.5%, and 4% withdrawal rates side-by-side so you can decide what risk level fits your situation.

Q6. What does the 10th percentile value mean in the simulation results?

A: The 10th percentile outcome shows your portfolio's value in the worst 10% of simulated scenarios. It's your downside floor — not a prediction, but a stress-test benchmark. If that number still covers your needs, your plan is resilient to bad market timing.

Q7. How is this different from a standard retirement calculator?

A: Standard calculators assume a fixed annual return (e.g., 7% every year). That's unrealistic. A Monte Carlo retirement simulator sequences returns randomly — capturing the danger of a market crash in Year 2 vs. Year 28. Sequence-of-returns risk is what actually kills retirement portfolios.

Q8. How do I use this simulator to refine my FIRE number?

A: Start with your target portfolio size and planned annual withdrawal. Set your expected retirement length (e.g., 40 years for early retirees). Adjust stock allocation until your success rate hits 90%+. The simulator shows exactly how each variable — savings, spending, timeline — shifts your odds of financial independence.