Beta Calculator

Compute a stock's beta from its returns and a benchmark's returns.

Stock returns (one per line, %)Market/benchmark returns (one per line, %)

Data points

Beta

1.533

R²

0.998

What this measures

Beta measures a stock's sensitivity to broad market moves. Beta = 1 means the stock moves with the market on average. Beta > 1 means it amplifies market moves (more volatile), < 1 means it dampens them (more defensive). Utility stocks often have beta ~0.5; small-cap tech often 1.3+.

Formula & example

Beta = Covariance(stock returns, market returns) ÷ Variance(market returns). Paste at least 12 paired returns (monthly is standard). The calculator computes covariance, variance, and beta. R² tells you how well the market explains the stock's variance — low R² means beta may be unreliable for that stock.