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Beta Calculator

Beta calculator: measure stock beta, market risk, and systematic risk using the beta formula to understand how a stock moves relative to the market

Frequently Asked Questions

What does beta measure?

A stock's sensitivity to market moves. Beta of 1.0 means it moves with the market; 1.5 means it moves 50% more than the market; 0.5 means it moves half as much. The market (S&P 500) has beta of 1.0 by definition.

What are typical betas by sector?

Utilities and consumer staples: 0.4-0.7 (defensive). Technology and consumer discretionary: 1.1-1.5. High-growth small caps and crypto-adjacent names: often above 2.0.

How is beta calculated?

Covariance(stock, market) / variance(market), typically using 3-5 years of monthly returns regressed against an index. Different providers use different windows, so betas can disagree noticeably for the same stock.

What is the difference between beta and total volatility?

Beta measures only systematic (market) risk. Total volatility (standard deviation) includes idiosyncratic risk specific to one company. A high-volatility stock can have low beta if it moves independently of the market.

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Investment Disclaimer: Estimates only. Not investment advice.

This calculator provides estimates for educational purposes only and is not investment advice. Past performance does not guarantee future results. Consult with a qualified financial advisor before making investment decisions. All investments carry risk, including potential loss of principal.

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How This Calculator Works

You paste two equal-length lists of periodic percentage returns - one for the stock and one for the market index - plus an annual risk-free rate and an expected market return. The tool returns beta, the stock-market correlation, both standard deviations, and a CAPM expected return, with a volatility-profile verdict. At least three paired observations are required.

Formula

β = Cov(stock, market) ÷ Var(market), using sample covariance and variance (dividing by n − 1). Correlation = Cov ÷ (σ₊ × σₘ). The CAPM expected return is E[R] = R₋ + β × (Rₘ − R₋), where (Rₘ − R₋) is the equity risk premium, historically about 5–7% in the U.S.

Worked Example

Suppose 10 paired observations yield Cov(stock, market) = 1.8 and Var(market) = 1.0, so β = 1.8 ÷ 1.0 = 1.80 - the stock is far more volatile than the index. With a 4.5% risk-free rate and 10% expected market return, CAPM = 4.5% + 1.80 × (10% − 4.5%) = 4.5% + 9.9% = 14.4% required return.

Beta in the Capital Asset Pricing Model (CAPM)

Beta is the central input to the Capital Asset Pricing Model, which specifies the return investors should expect from a risky asset. The CAPM formula is:

Expected Return = Risk-Free Rate + Beta × (Market Return − Risk-Free Rate)

The term (Market Return − Risk-Free Rate) is the equity risk premium (ERP) - the extra return the market pays for bearing equity risk. Historically this has been approximately 5–7% annualized for the U.S. stock market above the risk-free rate. A stock with beta 1.5 demands 1.5 times the ERP to compensate investors for its extra systematic risk. If the ERP is 6%, a beta-1.5 stock requires 9% above the risk-free rate to justify the investment.

In corporate finance, CAPM is widely used to estimate the cost of equity in discounted cash flow (DCF) models. The cost of equity feeds into the weighted average cost of capital (WACC), which discounts future free cash flows back to present value. CAPM's practical limitations are well-documented: it assumes returns are normally distributed (real-world fat tails violate this), that beta is stable over time (it shifts with business mix and capital structure), that all risk is captured in a single market factor (multi-factor models like Fama-French often explain returns better), and that the market portfolio is the correct benchmark (which itself is not directly observable).

Interpreting Beta by Sector

Beta varies systematically across industries, reflecting differences in revenue cyclicality, operating leverage, and capital intensity.

Defensive / Low-Beta Sectors

Utilities (electric, gas, water) typically carry betas in the 0.3–0.6 range. Revenues are regulated and relatively stable regardless of the economic cycle, and the stocks are often bought for their dividend income rather than capital appreciation. Consumer staples (food, beverages, household products) and healthcare (pharmaceuticals, medical devices) similarly cluster below 0.8 because demand for these products is non-discretionary. During market downturns these sectors tend to outperform on a relative basis, acting as portfolio stabilizers.

Cyclical / High-Beta Sectors

Semiconductors are among the highest-beta equities in the broad market, often showing betas of 1.5–2.5 due to extreme revenue cyclicality (end-markets span consumer electronics, automotive, industrial, and AI infrastructure) and high operating leverage. Small-cap growth stocks tend to show elevated betas because they have less diversified revenue, higher debt relative to earnings, and are more sensitive to changes in interest rates and credit availability. Financials (banks, insurers) generally sit in the 1.0–1.4 range, moving more than the market during financial stress but less than pure cyclicals during normal expansions.

Negative-Beta Assets

A handful of assets have historically shown negative or near-zero beta relative to the S&P 500. Gold is the classic example: it often appreciates during equity market stress as investors seek safe havens. Long-volatility strategies (such as long VIX positions) gain when markets fall sharply. These negative-beta assets are valuable portfolio diversifiers but typically have negative expected returns over long periods if held in isolation, since the CAPM model implies they should yield less than the risk-free rate.

Adjusted Beta and Rolling Beta

Raw (historical) betas are noisy because they are estimated from a limited return sample and because a company's true beta changes over time as its business mix and capital structure evolve. Two adjustments are commonly applied.

The Blume adjustment (named after researcher Marshall Blume) accounts for the empirical tendency of betas to regress toward 1.0 over time. The adjusted formula is: Adjusted Beta = 0.67 × Raw Beta + 0.33. A raw beta of 1.8 adjusts to 1.54, which reflects the expectation that the stock's sensitivity to the market will moderate toward average. Bloomberg and many professional data providers report Blume-adjusted betas by default.

Rolling beta tracks how beta changes across different estimation windows. A one-year rolling beta captures the stock's recent market sensitivity (useful for detecting regime shifts) while a five-year rolling beta provides a more stable long-run estimate. Comparing the two can reveal whether a stock has recently become more or less sensitive to the market, which is valuable information when macro conditions change.

For comparing betas across companies with different capital structures, analysts use unlevered (asset) beta, which strips out the amplifying effect of debt. A highly leveraged firm looks riskier (higher equity beta) than a conservatively financed peer with the same underlying business. The Hamada equation unleverages beta as: Asset Beta = Equity Beta ÷ (1 + (1 − Tax Rate) × Debt/Equity).

Common Mistakes

Supplying stock and market lists of different lengths or misaligned periods.
Mixing daily, weekly, and monthly returns within one list.
Reading beta as total risk - it captures only systematic (market) risk.
Ignoring correlation; a low R² means beta explains little of the stock's movement.
Treating a historical beta as fixed - it drifts over time.

Tips & FAQ

What does beta = 1 mean? The stock moves roughly in line with the market.

Can beta be negative? Yes - inverse ETFs and some gold miners move opposite the index.

Does a high-beta stock always give higher returns? In theory, CAPM says yes - higher systematic risk should be rewarded with higher expected returns over time. In practice, the evidence is mixed. The "low-beta anomaly" documented by researchers shows that low-beta stocks have historically delivered better risk-adjusted returns than high-beta stocks, partly because institutional investors use leverage constraints that cause them to tilt toward high-beta stocks (driving up prices and compressing future returns). High beta guarantees higher volatility but not reliably higher long-run absolute returns.

How is beta different from volatility? Volatility (standard deviation of returns) measures total risk: both market risk and company-specific (idiosyncratic) risk. Beta measures only the portion of a stock's risk that is correlated with the market. A biotech company with lumpy clinical-trial outcomes can have very high total volatility but a low beta if its stock moves mostly on company-specific news rather than market swings. Volatility is the right input for options pricing; beta is the right input for portfolio construction and CAPM cost-of-equity estimation.

Where do published betas come from? Sources like Yahoo Finance use 5-year monthly returns versus the S&P 500.