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Stock Beta Calculator
Calculate beta against the S&P 500, Nasdaq 100, or Russell 2000 over 1, 3, or 5 years. See annualized volatility, correlation, Sharpe ratio, and how beta feeds into your cost of equity for WACC and DCF valuation.
What Is Stock Beta?
Beta (β) measures a stock's sensitivity to market movements. It answers the question: when the market moves 1%, how much does this stock typically move? A beta of 1.0 means the stock tracks the market almost exactly. A beta of 1.5 means it tends to move 50% more than the market in either direction.
Beta is calculated from historical daily returns, using the covariance of a stock's returns with the market's returns divided by the variance of the market's returns. A longer lookback period (3Y or 5Y) gives a more stable, long-run estimate. A shorter period (1Y) is more responsive to recent volatility regimes.
How to Interpret Beta
| Beta Range | Label | What It Means |
|---|---|---|
| < 0 | Inverse | Moves opposite to the market (e.g., gold miners in some regimes) |
| 0 – 0.8 | Defensive | Lower volatility than market — utilities, consumer staples |
| 0.8 – 1.2 | Market-Level | Tracks the market closely — typical large-cap blended funds |
| 1.2 – 1.5 | Elevated | Moderately more volatile than market — growth tech, financials |
| > 1.5 | High Sensitivity | Strongly amplified moves — small caps, high-growth, leveraged |
Beta is backward-looking — it describes how a stock has behaved relative to the market, not how it will behave. Beta can shift over time as a company's leverage, business mix, or market regime changes. A 5-year beta for a tech company that recently pivoted to enterprise SaaS may not reflect its current risk profile.
Beta's Role in WACC and DCF Valuation
Beta is the linchpin of the Capital Asset Pricing Model (CAPM), which estimates the cost of equity — the return required to compensate shareholders for market risk:
Where Rf is the risk-free rate (typically the 10-year Treasury yield, ~4.5%) and ERP is the equity risk premium (the additional return investors demand for owning stocks over bonds, historically 5–5.5%). A stock with β = 1.4 requires a cost of equity of 4.5% + 1.4 × 5.5% = 12.2%. The same stock with β = 0.7 requires only 4.5% + 0.7 × 5.5% = 8.35%.
This discount rate feeds directly into WACC and ultimately determines the present value of future cash flows in a DCF model. A 1-point increase in beta raises the cost of equity by 5.5% — which can reduce a stock's fair value by 20–40% depending on growth assumptions and terminal value. Beta is not just a risk number; it is a valuation driver. Use the WACC Calculator to build the full weighted average cost of capital, and the DCF Calculator to apply it to intrinsic value.
Beta vs. Total Volatility: What's the Difference?
Beta measures systematic risk — the portion of a stock's volatility that comes from market-wide movements and cannot be diversified away. Annualized volatility (shown in the calculator) measures total risk, including company-specific (idiosyncratic) risk that can be reduced by holding a diversified portfolio. A stock can have high total volatility but low beta if its price swings are driven by company-specific news (earnings surprises, product launches, management changes) rather than market moves. Biotech stocks are a classic example: extremely volatile, but often with moderate beta because their catalysts are event-driven, not macro-driven.
For valuation purposes, beta is what matters. CAPM and WACC are built around systematic risk, not total volatility. Idiosyncratic risk is theoretically diversifiable and should not command a risk premium in a well-diversified portfolio. In practice, however, very small or illiquid stocks may deserve a size premium on top of CAPM cost of equity — a common adjustment in professional appraisals.
How the Beta Calculator Works
Data & Calculation Method
Beta is calculated from daily closing prices via Yahoo Finance. For each date where both the stock and benchmark have a valid close, we compute the simple daily return (close_t / close_{t-1} − 1). Beta = Covariance(stock, benchmark) / Variance(benchmark), using the sample covariance (n−1 denominator).
A minimum of 20 data points is required. For 1Y, you'll typically have ~252 data points; 3Y gives ~756; 5Y gives ~1,260.
Correlation
Correlation measures how closely the stock's daily returns track the benchmark — from −1 (perfectly inverse) to +1 (perfectly aligned). It is the normalized version of covariance: Corr = Cov(stock, bench) / (σ_stock × σ_bench).
High correlation + high beta = the stock reliably amplifies market moves. High beta + low correlation = the stock is volatile but for different reasons than the market.
Annualized Volatility
Annualized volatility = daily standard deviation of returns × √252. It measures total price risk regardless of market direction. A stock at 35% annualized vol will, on average, swing ±35% from its starting price over a year (one standard deviation).
Higher vol requires higher expected return to compensate. Compare to beta: vol is total risk, beta is only the market-correlated portion.
Sharpe Ratio
Sharpe = (Annualized Return − Risk-Free Rate) / Annualized Volatility. It measures return per unit of total risk, using 4.5% as the risk-free rate. A Sharpe above 1.0 is generally considered good; above 2.0 is excellent.
Hover over the Sharpe number in results for the tooltip. Note: Sharpe is backward-looking and sensitive to the time period chosen.
How to Use This Beta Calculator
Enter any US-listed ticker
Type the stock symbol (e.g. AAPL, NVDA, JPM) and press Calculate. The tool fetches daily price data from Yahoo Finance and computes beta in real time against your chosen benchmark.
Choose period and benchmark
Use 1Y for a recent snapshot of volatility regime. Use 3Y or 5Y for a stable long-run estimate. S&P 500 (SPY) is the standard reference; Nasdaq 100 (QQQ) is better for comparing tech stocks against peers; Russell 2000 (IWM) for small-cap context.
Read the WACC implication
Below the results, the WACC card shows the implied cost of equity at the calculated beta (using Rf=4.5%, ERP=5.5%). This is your starting discount rate for DCF valuation. Feed it into the WACC Calculator to build a full capital structure-weighted rate.
Use beta in a full valuation
Beta alone doesn't tell you if a stock is cheap or expensive. Combine it with ROIC (to see if the company earns above its cost of equity), DCF (to apply the discount rate), and the earnings quality score (to validate the cash flows you're discounting).
Frequently asked questions
What is beta in stocks?
Beta is a measure of a stock's volatility relative to the overall market. A beta of 1.0 means the stock moves in line with the market. Beta above 1.0 means higher volatility; below 1.0 means lower volatility. It's used in CAPM to estimate the cost of equity required to compensate investors for market risk.
How is beta calculated?
Beta = Covariance(stock returns, market returns) / Variance(market returns). In practice, this is computed from a regression of daily stock returns against daily market returns over a historical period (typically 1–5 years). A slope coefficient greater than 1 means the stock is more volatile than the market.
What is a beta of 1.5?
A beta of 1.5 means the stock historically moves 1.5x as much as the market. If the S&P 500 rises 10%, the stock would be expected to rise approximately 15%. If the market falls 10%, the stock would typically fall 15%. High-beta stocks offer more upside in bull markets but larger losses in downturns.
Is a beta of 0.5 good?
It depends on your goals. A beta of 0.5 indicates the stock is half as volatile as the market — a defensive characteristic favored by income investors, retirees, and those prioritizing capital preservation. However, lower beta generally means lower expected returns over full market cycles, per CAPM.
What does negative beta mean?
A negative beta means the stock tends to move opposite to the market — when the market falls, the stock rises, and vice versa. Gold and some commodities exhibit this trait during risk-off periods. It's rare for equities but can appear for inverse ETFs or in specific market regimes.
How does beta relate to WACC?
Beta is used to estimate cost of equity via CAPM: Ke = Rf + β × ERP. This cost of equity is a major component of WACC (Weighted Average Cost of Capital). A higher beta raises Ke, which raises WACC, which lowers the present value of future cash flows in a DCF model.
What is a good beta for a stock?
There is no universally 'good' beta — it depends on your investment objective. Defensive investors prefer beta < 1 (utilities, consumer staples). Growth investors accept beta > 1 for amplified returns. Value investors look for stocks where the beta-implied discount rate understates actual earnings quality.
Why does beta change over time?
Beta is estimated from historical returns and shifts as a company's leverage, business mix, or competitive position changes. A tech company that pivots from growth to mature cash flows will see its beta decline. Financial stress can spike beta as the stock becomes more sensitive to macro news. Use 3Y or 5Y for stability; 1Y for a current-regime estimate.