Beta Stock Calculator

Background.

Use Beta Stock Calculator when you need to calculate covariance of stock and market returns divided by market-return variance. Beta measures historical linear sensitivity to the chosen market series, not standalone volatility or expected return. Here the arithmetic follows “stock beta = covariance(stock return, market return) / variance(market return),” rather than silently mixing alternatives.

The editable entries are covariance of stock and market returns, variance of market returns. Use values from the document or measurement that governs this beta stock question; the defaults are only the worked fixture below. The most consequential input mistake would be to ignore that return frequency, benchmark, date window, dividends and outliers can materially change the estimate.

Kenneth French Data Library; market return series and research factors documents the convention or governing rule used here. The beta stock output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is beta stock calculator?

Beta Stock is the relationship behind this decision: beta measures historical linear sensitivity to the chosen market series, not standalone volatility or expected return. On this page it means stock beta = covariance(stock return, market return) / variance(market return). Return frequency, benchmark, date window, dividends and outliers can materially change the estimate; that is the line between the reported quantity and a broader investing analysis.

How to use this calculator.

1. 01Confirm that “stock beta = covariance(stock return, market return) / variance(market return)” matches the beta stock convention you need.
2. 02Replace the fixture values for covariance of stock and market returns, variance of market returns with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read stock beta together with this boundary: Return frequency, benchmark, date window, dividends and outliers can materially change the estimate.

The formula.

The calculation uses stock beta = covariance(stock return, market return) / variance(market return). In this beta stock model, the entered terms are covariance of stock and market returns, variance of market returns. Beta measures historical linear sensitivity to the chosen market series, not standalone volatility or expected return, which is why the relationship is presented under this name rather than as a universal alternative. Return frequency, benchmark, date window, dividends and outliers can materially change the estimate. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Kenneth French Data Library; market return series and research factors. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]U.S. Securities and Exchange Commission. Investor.gov glossary: Beta. Retrieved 2026-08-07. independence: primary; access: open.
3. [3]U.S. Securities and Exchange Commission. Investor.gov: Assessing your risk tolerance. Retrieved 2026-08-07. independence: secondary-check; access: open.