Beta (Stock) Calculator

Calculate a stock's beta coefficient, alpha, R-squared, and correlation from historical returns. Includes unlevered beta and CAPM expected return.

About the Beta (Stock) Calculator

Beta is one of the most important metrics in finance. It measures a stock's sensitivity to market movements — how much a stock tends to move for every 1% change in the overall market. A beta of 1.0 means the stock moves roughly in lockstep with the market. A beta above 1.0 indicates higher volatility (and potentially higher returns), while a beta below 1.0 suggests lower volatility.

Understanding beta is essential for portfolio construction, risk management, and valuation. Investors use beta to determine expected returns through the Capital Asset Pricing Model (CAPM), assess diversification benefits, and gauge whether individual stocks align with their risk tolerance.

This calculator computes beta from raw return data by performing a covariance/variance regression against a market benchmark. It also calculates alpha (outperformance), correlation, R-squared, and the unlevered beta for companies with debt. The return-pair table and risk gauge visualize the relationship between the stock and the market.

Why Use This Beta (Stock) Calculator?

Beta is widely quoted but often misunderstood. This calculator lets you compute beta from your own data rather than relying on third-party providers. You can verify reported betas, analyze different time periods, and understand the statistical strength of the relationship through R-squared and correlation. Keep these notes focused on your operational context.

How to Use This Calculator

  1. Enter the stock's periodic returns as comma-separated percentages (e.g., monthly or annual returns).
  2. Enter the market benchmark returns for the same periods.
  3. Enter the current risk-free rate (e.g., 10-year Treasury yield).
  4. Enter the market risk premium for CAPM expected return calculation.
  5. Optionally enter the company's debt-to-equity ratio and tax rate for unlevered beta.
  6. Review beta, alpha, correlation, and R-squared outputs.
  7. Use the return pairs table to see how individual periods contributed to the beta estimate.

Formula

β = Cov(Rₛ, Rₘ) / Var(Rₘ) α = R̄ₛ − [Rf + β × (R̄ₘ − Rf)] Unlevered β = β / [1 + (1 − Tax) × D/E] CAPM Expected Return = Rf + β × Market Risk Premium

Example Calculation

Result: β ≈ 1.22

The stock has a beta of about 1.22, meaning it moves ~22% more than the market. With a risk-free rate of 3% and market premium of 7%, the CAPM expected return is 3% + 1.22 × 7% = 11.54%.

Tips & Best Practices

Practical Guidance

Use consistent units, verify assumptions, and document conversion standards for repeatable outcomes.

Common Pitfalls

Most mistakes come from mixed standards, rounding too early, or misread labels. Recheck final values before use. ## Practical Notes

Use this for repeatability, keep assumptions explicit. ## Practical Notes

Track units and conversion paths before applying the result. ## Practical Notes

Use this note as a quick practical validation checkpoint. ## Practical Notes

Keep this guidance aligned to expected inputs. ## Practical Notes

Use as a sanity check against edge-case outputs. ## Practical Notes

Capture likely mistakes before publishing this value. ## Practical Notes

Document expected ranges when sharing results.

Frequently Asked Questions

What does a beta of 1 mean?

A beta of 1 means the stock moves in line with the market. If the market goes up 10%, the stock is expected to go up about 10%.

Is a high beta good or bad?

Neither inherently. High beta means more volatility, which means higher potential returns but also larger drawdowns. It depends on your risk tolerance.

What is unlevered beta?

Unlevered beta removes the effect of financial leverage (debt). It reflects the business risk alone, making it useful for comparing companies with different capital structures.

How many data points do I need?

Generally, 30+ monthly returns (2.5 years) give a statistically meaningful beta. Fewer points increase estimation error.

What is R-squared in this context?

R-squared tells you what percentage of the stock's variance is explained by market movements. A low R-squared means beta is a weak predictor of the stock's behavior.

Can beta be negative?

Yes. A negative beta means the stock tends to move opposite to the market. Gold stocks and some hedge fund strategies sometimes exhibit negative beta.

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