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Beta Stock Calculator
Estimate a stock’s beta, a measure of its volatility relative to the overall market, from covariance and variance inputs.
What is beta?
Beta measures how volatile a stock is compared to the overall market. A beta of 1 means the stock tends to move with the market; above 1 means it tends to swing more than the market; below 1 means it tends to be more stable than the market.
The formula
Beta = Covariance(Stock Returns, Market Returns) / Variance(Market Returns). In practice, analysts calculate covariance and variance from historical return data, often using a benchmark index like the S&P 500 as ‘the market.’
This tool is for general educational purposes. Beta is based on historical data and does not guarantee how a stock will behave in the future.
Last reviewed August 2026