Interactive Calculator #
🎲 Monte Carlo Retirement Calculator
Simulate your financial future with 100,000+ scenarios
1. Choose Your Portfolio
Heavy dividend tilt with growth
- VTI: 35% • SCHG: 15%
- SCHD: 30% • SGOV: 20%
Ultimate simple, diversified portfolio
- VTI: 54% • VXUS: 26%
- BND: 20%
All market conditions with gold
- VTI: 30% • VXUS: 10%
- SHY: 20% • TLT: 20% • GLD: 20%
Enhanced diversification + inflation
- VTI: 40% • VXUS: 20%
- VNQ: 10% • VTIP: 15% • BND: 15%
2. Set Your Parameters
How to Use This Calculator #
Step 1: Choose Your Portfolio #
Select from four professionally designed portfolios:
| Portfolio | Best For | Expected Return |
|---|---|---|
| Dividend-Focused | Income seekers, US-focused investors | 8.0% |
| Three-Fund Bogleheads | Most investors (lowest fees, global diversification) | 7.0% |
| Golden Butterfly | Conservative investors worried about crashes | 6.5% |
| Modern Bogleheads | Inflation-conscious investors | 7.2% |
Step 2: Set Your Withdrawal Rate #
This determines how much you withdraw annually. The calculator supports two strategies:
Constant Dollar (Traditional): Fixed inflation-adjusted withdrawals regardless of portfolio value. Simple but rigid.
Dynamic Spending (Vanguard): Withdrawals adjust based on portfolio performance with floor/ceiling bounds. More sustainable for aggressive rates.
Quick guide:
- 2.5-3.0% = Very conservative (50-year horizons)
- 3.0-3.5% = Moderate (40-year horizons)
- 4.0%+ = Aggressive (30-year horizons or with flexibility)
Step 3: Set Duration #
Enter years until age 100 (or your planning horizon). Add 5-10 years as a buffer.
Step 4: Add Fees (Optional) #
Beyond ETF expense ratios, add any advisor or platform fees:
- 0.00% - DIY at Vanguard/Fidelity/Schwab
- 0.25% - Robo-advisors
- 1.00% - Traditional advisor (costs ~39% of wealth over 50 years!)
Step 5: Run Simulation #
Click Run Simulation and wait 2-10 seconds. The calculator runs 10,000+ scenarios.
Understanding Your Results #
| Metric | What It Means |
|---|---|
| Median Outcome | Most likely result (50th percentile) |
| 5th Percentile | Your safety net—plan around this number |
| Depletion Risk | Probability of running out of money |
| Sharpe/Sortino Ratio | Risk-adjusted returns (higher = better) |
| Max Drawdown | Worst peak-to-trough drop |
Depletion risk guidelines:
- 0-5% = Very safe
- 5-10% = Acceptable
- 10%+ = Consider reducing withdrawal rate
Advanced Options #
Fat-Tail Mode: Models extreme events (crashes and booms) more realistically using Student’s t-distribution instead of normal distribution. Recommended for conservative planning.
Dynamic Spending Bounds: Adjust floor (-2.5% default) and ceiling (+5% default) to control withdrawal variability.
Privacy & Accuracy #
All calculations run in your browser. No data is collected or stored.
The simulator uses monthly-level precision, Cholesky decomposition for correlated returns, geometric mean returns, and annual rebalancing—matching professional-grade Monte Carlo methodology.