Free alpha and beta calculator. Measure your portfolio's market sensitivity (beta) and excess risk-adjusted return (alpha) against a benchmark index.
The Alpha and Beta Calculator helps you understand two critical dimensions of investment performance: how sensitive your portfolio is to market movements (beta) and how much excess return you generate beyond what the market explains (alpha). These metrics are cornerstones of the Capital Asset Pricing Model (CAPM) and modern portfolio theory.
Beta measures systematic risk. A beta of 1.0 means your portfolio moves in lockstep with the market. A beta above 1.0 indicates higher volatility than the market, while a beta below 1.0 suggests lower volatility. Understanding beta helps you calibrate your portfolio's risk exposure to match your tolerance.
Alpha represents the value a manager or strategy adds beyond what would be expected given the portfolio's level of market risk. Positive alpha means you outperformed on a risk-adjusted basis; negative alpha means you underperformed. Consistently generating positive alpha is the holy grail of active management. Understanding these metrics helps you separate skill from market exposure when evaluating any fund or trading strategy.
Knowing your portfolio's beta helps you understand how much of your returns come from broad market exposure versus skill. Alpha separates luck and market tailwinds from genuine outperformance. Together, these metrics let you evaluate whether active management fees are justified or whether you would be better served by a low-cost index fund.
Beta = (Correlation × σ_portfolio) / σ_market Alternatively: Beta = Cov(Ri, Rm) / Var(Rm) Alpha (Jensen's Alpha) = Rp – [Rf + Beta × (Rm – Rf)] where Rp = portfolio return, Rm = market return, Rf = risk-free rate, σ = standard deviation
Result: Beta: 1.13, Alpha: 3.2%
With a correlation of 0.85 between the portfolio and market, beta = (0.85 × 20%) / 15% = 1.13. The expected return per CAPM = 4% + 1.13 × (10% – 4%) = 10.8%. Actual return is 14%, so alpha = 14% – 10.8% = 3.2%. The portfolio outperformed its risk-adjusted expectation by 3.2 percentage points.
CAPM is a widely used benchmark for relating expected return to market sensitivity (beta) and the risk-free rate. The result is a planning estimate, not a guarantee of future performance, and any difference from that estimate is often discussed as alpha.
The most common approach uses regression analysis on historical returns. Plot portfolio returns against benchmark returns, and the slope of the best-fit line is beta. Alternatively, calculate beta as the correlation times the ratio of portfolio volatility to market volatility. Both methods yield the same result with properly computed inputs.
Alpha is most useful when you are comparing actual return to a beta-based expectation over the same time window. A persistent positive value can suggest skill, but it can also reflect model limitations or luck, so it should be treated as a worksheet result rather than proof of outperformance.
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This calculator applies the CAPM relationship expected return = risk-free rate + beta × market risk premium. It also calculates beta and Jensen-style alpha from the same return series inputs so the output can be read as a simple benchmark worksheet.
The page is intended for comparison and attribution only. It does not forecast future returns or prove skill by itself.
A beta of 1.5 means the portfolio tends to move 1.5 times as much as the market. If the market rises 10%, the portfolio is expected to rise about 15%. Conversely, if the market falls 10%, the portfolio is expected to fall about 15%. Higher beta means higher systematic risk.
Jensen's alpha is the difference between the portfolio's actual return and the return predicted by the CAPM given the portfolio's beta. Positive alpha indicates that the portfolio outperformed its risk-adjusted benchmark, while negative alpha indicates underperformance.
Yes, though it is rare. A negative beta means the asset tends to move opposite to the market. Gold and certain hedge fund strategies sometimes exhibit slightly negative beta. A portfolio with negative beta can serve as a hedge during market downturns.
Volatility (standard deviation) measures total risk including both systematic and unsystematic components. Beta measures only systematic risk, which is the portion related to broad market movements. A stock can be highly volatile but have a low beta if its movements are uncorrelated with the market.
Sustained positive alpha is very difficult to achieve. Academic research shows that most active managers fail to consistently beat their benchmarks after fees. Some skilled managers and certain systematic strategies can generate alpha, but it tends to diminish as more capital chases the same opportunities.
Ideally, calculate the actual correlation from historical return data. As a rough guide, a diversified U.S. equity portfolio typically has a correlation of 0.85 to 0.95 with the S&P 500. International or alternative investments will have lower correlations.
The Capital Asset Pricing Model states that expected return = risk-free rate + beta × market risk premium. Alpha measures the deviation from this prediction. If CAPM perfectly described reality, alpha would always be zero. Persistent non-zero alpha suggests either skill, luck, or model limitations.
It depends on your risk tolerance and market outlook. Conservative investors prefer low-beta portfolios for smoother rides. Aggressive investors may choose high-beta portfolios to amplify returns during bull markets. The key is matching beta to your personal risk profile and investment horizon.