Portfolio Visualizer

Portfolio Visualizer lets you test your proposed allocation against decades of historical market data before you invest real money. You enter your target mix of stocks, bonds, and other assets, then run a backtest to see how it would have performed during past bull markets, crashes, and sideways years. The tool also runs Monte Carlo simulations to show the range of possible outcomes and the odds of success given your withdrawal rate and time horizon.

This is built for investors who want to stress-test their strategy or verify that their allocation makes sense historically. If you're in your accumulation phase, backtesting may feel less relevant, but as you approach retirement or start living off your portfolio, seeing how your mix would've held up in 2008 or 2000 becomes valuable. The free version covers most use cases; paid tiers open more assets and advanced tools for fine-tuning.