What is a Portfolio Backtester?
A portfolio backtester is an analytical tool that simulates how a specific combination of investments would have performed over a historical time period. By using real historical price data, investors can evaluate the risk and return characteristics of a portfolio before committing real capital. Our free portfolio backtester lets you build a custom portfolio of stocks and ETFs, assign allocation weights, and instantly see how it would have performed compared to the S&P 500 benchmark. Whether you are testing a classic 60/40 stock-bond split or an aggressive growth portfolio, backtesting provides data-driven insights that help you make better investment decisions.
How to Use This Portfolio Backtester
- 1
Build Your Portfolio
Search for stocks or ETFs by ticker symbol and add them to your portfolio. Alternatively, select one of the preset portfolios like the 60/40 Portfolio, Tech Giants, or Dividend Aristocrats to get started quickly.
- 2
Set Allocation Weights
Assign a percentage weight to each holding. Weights must total 100%. Use the "Equalize Weights" button to distribute evenly across all holdings.
- 3
Configure Backtest Settings
Choose a start date, end date, initial investment amount, and rebalancing frequency (none, monthly, quarterly, or annually).
- 4
Analyze the Results
Review total return, annualized return, maximum drawdown, Sharpe ratio, and volatility. Compare your portfolio performance against the S&P 500 benchmark in the interactive chart and yearly returns table.
Key Metrics Explained
Understanding the metrics produced by a backtest is essential for making informed investment decisions. Here are the key metrics our backtester calculates:
Total Return
The overall percentage gain or loss of the portfolio from start to end, including the effect of compounding.
Annualized Return
The geometric average annual return, which accounts for compounding and provides a standardized way to compare investments over different time periods.
Maximum Drawdown
The largest peak-to-trough decline in portfolio value. This measures the worst-case scenario an investor would have experienced during the backtest period.
Sharpe Ratio
A measure of risk-adjusted return. Higher values indicate better returns per unit of risk taken. A Sharpe ratio above 1.0 is generally considered good.
Volatility
The annualized standard deviation of daily returns. Higher volatility means larger price swings and more uncertainty in short-term outcomes.
Rebalancing
Periodically adjusting holdings back to target weights. Rebalancing can reduce risk by preventing any single position from dominating the portfolio.
Why Use Our Portfolio Backtester?
Real Historical Data
Powered by adjusted close prices that account for stock splits and dividends, ensuring accurate historical simulations.
100% Free
No registration, no subscription, no hidden fees. Professional-grade portfolio analysis available to everyone.
Preset Portfolios
Start instantly with popular portfolio templates like the 60/40 Portfolio, Tech Giants, or Dividend Aristocrats.