Sharpe Ratio Calculator
Measure excess return per unit of volatility using a consistent return period for all three inputs.
Inputs
Live results
The investment earns 0.67 units of excess return for each unit of volatility.
Calculation detail
| Measure | Formula | Current value |
|---|---|---|
| Asset return | Input | 10.00% |
| Risk-free return | Input | 2.00% |
| Risk premium | Asset return – risk-free return | 8.00% |
| Standard deviation | Input volatility | 12.00% |
| Sharpe ratio | Risk premium ÷ standard deviation | 0.67 |
How to use the Sharpe ratio calculator
What this calculator does
This calculator estimates the Sharpe ratio, a risk-adjusted performance measure that compares an investment's return above a risk-free benchmark with the volatility of that investment's returns. It answers a focused question: how much excess return was earned, or is expected, for each unit of total return variability? It does not determine whether an investment is suitable for you, forecast future returns, measure downside risk separately, or account for fees, taxes, liquidity, drawdowns, skewness, or changing market conditions unless those effects are already reflected in your return data.
When to use it
Use the calculator to compare two funds measured over the same period, review whether a portfolio change improved risk-adjusted performance, assess a strategy against a consistent cash or Treasury benchmark, or check the effect of a different return or volatility assumption. Comparisons are most meaningful when the investments use the same sampling frequency, time horizon, return convention, and risk-free benchmark.
How to calculate
- The calculator opens with a complete demonstration: a 10.00% asset return, 2.00% risk-free return, and 12.00% standard deviation. Its results and example XLSX workbook are immediately available.
- Replace each percentage with your own figures. Enter plain decimals such as 8.5 for 8.5%; a trailing percent sign is also accepted. Commas, scientific notation, and mixed text are rejected to avoid ambiguous interpretation.
- Read the Sharpe ratio first, then confirm the risk premium and volatility used. The calculation updates live.
- Select Download Excel to export the current validated inputs and outputs as a real workbook. Select Reset to clear the demonstration and results; export remains disabled until all required values are complete and valid again.
Input guide
Return on asset or investment is required and accepts a finite percentage from – 1,000% to 1,000%. It may be an expected return or a realized average return, but it must use the same period as the other inputs. A realistic example is 10.00%. Raising this input increases the risk premium and Sharpe ratio one-for-one before division by volatility. A common mistake is entering 0.10 to mean 10%; here, enter 10.
Risk-free return is required and accepts a finite percentage from – 100% to 1,000%. A realistic example is 2.00%. Raising it reduces the risk premium and therefore lowers the Sharpe ratio. Choose a benchmark with a comparable horizon and currency. The CFA Institute describes the ratio as excess return divided by the standard deviation of excess return in its overview of volatility-adjusted performance.
Standard deviation is required, is expressed as a percentage, and must be greater than 0% and no more than 1,000%. A realistic example is 12.00%. Higher volatility lowers the Sharpe ratio when the risk premium is unchanged. Do not use variance, beta, maximum drawdown, or a standard deviation calculated from a different return frequency.
Output guide
Sharpe ratio is a unitless comparison: risk premium divided by standard deviation. A value of zero means the asset return equals the risk-free return. A negative value means the investment underperformed the benchmark over the selected period. Higher values indicate more excess return per unit of volatility, but labels such as “good” or “strong” are only broad context and should not replace peer comparison or statistical judgment. Risk premium is the asset return minus the risk-free return, shown as a percentage. Volatility used repeats the standard deviation supplied so the denominator is easy to audit. The summary pills present the same canonical values in compact form, and the calculation-detail table lists every input, formula step, and current result.
Worked example
With the startup values, the risk premium is 10.00% – 2.00% = 8.00%. Dividing 8.00% by 12.00% gives 0.6667, displayed as a Sharpe ratio of 0.67. This means the example earns about 0.67 units of return above the benchmark for each unit of measured volatility. The workbook stores the input percentages as decimal fractions and the Sharpe ratio as a numeric value, so the calculation remains reproducible.
Formula and interpretation
Sharpe ratio = (asset return – risk-free return) ÷ standard deviation
The ratio is most useful as a relative measure. A higher number can result from a higher return, a lower benchmark, lower volatility, or a combination of those changes. It is not a complete risk report: standard deviation treats upside and downside variation alike and can be less informative when returns are highly skewed, autocorrelated, or shaped by rare losses. The Federal Reserve Bank of Boston discusses practical use and limitations in its paper on risk-adjusted mutual fund performance.
Keeping periods consistent
If returns are monthly, use a monthly risk-free rate and monthly standard deviation. Annualizing generally requires consistent compounding and, under common independence assumptions, volatility is scaled by the square root of the number of periods. Those assumptions can fail when returns are serially correlated. For broader investor context on risk and diversification, review the U.S. SEC's introduction to investment risk. This calculator is educational and does not provide personalized investment advice.