Sharpe Ratio Calculator
Created by: Ethan Brooks
Last updated:
Calculate the Sharpe ratio of a portfolio or investment — the excess return per unit of volatility. Enter the portfolio return, risk-free rate, and standard deviation to get the risk-adjusted performance score and interpretation.
Sharpe Ratio Calculator
FinanceMeasure risk-adjusted return — how much excess return you earn per unit of portfolio volatility.
What Is a Sharpe Ratio Calculator?
A Sharpe ratio calculator measures the risk-adjusted performance of a portfolio or investment by dividing its excess return (above the risk-free rate) by its standard deviation.
The result tells you how much return you are earning per unit of volatility — a higher ratio means better risk-adjusted performance.
Developed by Nobel laureate William Sharpe in 1966, the Sharpe ratio is one of the most widely used metrics in portfolio management for comparing investments on an apples-to-apples, risk-adjusted basis.
How the Sharpe Ratio Is Calculated
The Sharpe ratio = (Portfolio Return − Risk-Free Rate) / Standard Deviation.
The numerator — excess return — is the return above what you could earn from a risk-free investment.
The denominator — standard deviation — measures the volatility (both upside and downside) of the portfolio's returns.
A portfolio returning 12% with a 15% standard deviation and a 4.5% risk-free rate has a Sharpe ratio of (12 − 4.5) / 15 = 0.5.
A portfolio returning 10% with an 8% standard deviation has a Sharpe ratio of (10 − 4.5) / 8 = 0.69 — better risk-adjusted performance despite lower absolute return.
Sharpe Ratio Formula
Sharpe Ratio = (Rp − Rf) / σp
Rp = Portfolio annualized return (%)
Rf = Risk-free rate (%)
σp = Portfolio annualized standard deviation (%)
Excess return = Rp − Rf
Example Scenarios
Comparing Two Portfolios
Portfolio A returns 14% with 18% standard deviation. Portfolio B returns 11% with 10% standard deviation. Risk-free rate: 4.5%. Sharpe A = (14−4.5)/18 = 0.53. Sharpe B = (11−4.5)/10 = 0.65. Portfolio B has a better risk-adjusted return despite lower absolute performance — investors taking less risk earn more per unit of that risk.
Evaluating Against the S&P 500
A managed fund returns 16% per year with 22% standard deviation. The S&P 500 returned 13% with 17% standard deviation over the same period. Risk-free rate: 4.5%. Fund Sharpe: (16−4.5)/22 = 0.52. S&P Sharpe: (13−4.5)/17 = 0.50. The fund barely beats the S&P on risk-adjusted terms — after fees, it likely underperforms.
Low Return, Low Risk Strategy
A conservative bond/equity blend returns 7.5% with 6% standard deviation. Sharpe = (7.5−4.5)/6 = 0.50. While the absolute return seems modest, the risk-adjusted return is comparable to a pure equity portfolio. This is the core argument for balanced portfolios: similar Sharpe ratio at much lower volatility.
How People Use This Calculator
- Comparing mutual funds or ETFs on a risk-adjusted basis
- Evaluating a portfolio manager's value-add beyond raw returns
- Screening hedge funds or alternative investments for risk efficiency
- Tracking a portfolio's risk-adjusted performance over time
- Optimizing asset allocation to maximize the Sharpe ratio of a portfolio
Sharpe Ratio Interpretation Tips
Always compare Sharpe ratios for the same time period and using the same risk-free rate.
A fund with a Sharpe of 1.2 in a low-rate environment is not the same as a Sharpe of 1.2 in a high-rate environment — the latter required generating substantially more return.
The Sharpe ratio is most reliable over long periods (5+ years) with consistent return data.
Over short periods, a lucky run of high returns can inflate the Sharpe ratio, and one volatile quarter can deflate it.
Use rolling Sharpe ratios to see how performance stability evolves.
For strategies with non-normal return distributions — such as options writing, merger arbitrage, or trend-following — consider the Sortino ratio (only penalizes downside deviation) or the Calmar ratio (return divided by max drawdown) as complementary metrics.
Frequently Asked Questions
What is the Sharpe ratio and what does it measure?
The Sharpe ratio measures risk-adjusted return — specifically, how much excess return an investment earns per unit of volatility (standard deviation). It was developed by William Sharpe in 1966. A higher Sharpe ratio means the investment generates more return for each unit of risk taken. A ratio below zero means the investment underperformed the risk-free rate. The Sharpe ratio is most useful for comparing similar investments or evaluating a portfolio's efficiency relative to its risk.
What is considered a good Sharpe ratio?
As a rough benchmark: below 0 is worse than the risk-free rate; 0–0.5 is below average; 0.5–1.0 is adequate; 1.0–2.0 is good; above 2.0 is excellent. The S&P 500 has historically averaged a Sharpe ratio of roughly 0.4–0.6 over long periods. Well-diversified portfolios rarely sustain ratios above 1.0 over long periods. Very high ratios (>3) often indicate either exceptional risk management, a short track record, or smoothed/infrequently priced returns that understate true volatility.
What risk-free rate should I use?
The risk-free rate is typically the yield on short-term government securities with no default risk. Common choices: the current 3-month U.S. Treasury bill rate for short-horizon analysis, or the 10-year Treasury yield for longer-term investment evaluation. The choice should match the investment horizon. In a high-rate environment (e.g., 4–5% T-bill), a portfolio must earn significantly more than 4–5% annually to show a positive Sharpe ratio — making the benchmark meaningfully higher than in the 2010s near-zero rate environment.
How is standard deviation estimated for the Sharpe ratio?
Standard deviation for Sharpe ratio purposes is typically the annualized standard deviation of periodic returns (monthly or daily). If you have n months of returns, calculate their standard deviation and multiply by √12 to annualize. This calculator accepts the annualized standard deviation directly. For a diversified equity portfolio, annualized standard deviation is commonly 15–20%. Individual stocks may have standard deviations of 25–50% or more.
What are the limitations of the Sharpe ratio?
The Sharpe ratio has several important limitations. It treats upside and downside volatility equally — an investment that generates large gains will be penalized the same as one with large losses. It assumes returns are normally distributed, which may not hold for strategies with fat tails or skewed payoffs (e.g., options strategies, hedge funds). It can be gamed by smoothing returns (reducing measured standard deviation). For non-normal return distributions, the Sortino ratio (which only penalizes downside volatility) may be more appropriate.
Sources and References
- Sharpe, W. F. (1966). "Mutual fund performance." Journal of Business.
- Sharpe, W. F. (1994). "The Sharpe ratio." Journal of Portfolio Management.
- CFA Institute: Measuring Portfolio Performance
- Morningstar Methodology: Risk-Adjusted Return Metrics