Enter daily, weekly, or monthly return percentages separated by commas
Annualized Vol = Daily StdDev x sqrt(252)
Standard deviation of periodic returns is annualized by multiplying by the square root of 252 (trading days per year).
Volatility is a statistical measure of the dispersion of returns for a given security or market index. It represents the degree of variation in an investment's price over time and is one of the most important concepts in finance. Higher volatility indicates greater uncertainty about the magnitude of an investment's price changes, meaning the price can change dramatically in either direction over a short period.
Investors and portfolio managers use volatility to assess risk, price options, set stop-loss levels, and determine appropriate position sizes. Historical volatility is calculated from past price data, while implied volatility is derived from options prices and reflects the market's expectation of future price movements.
Historical volatility is calculated by first computing the mean (average) of a set of periodic returns. Then, the variance is found by averaging the squared deviations from the mean. The standard deviation (square root of variance) gives the periodic volatility. To annualize daily volatility, multiply by the square root of 252 (the approximate number of trading days in a year).
For example, if daily returns have a standard deviation of 1.5%, the annualized volatility would be approximately 1.5% x sqrt(252) = 23.8%. This means you can expect the investment's annual return to deviate from the mean by about 23.8% one standard deviation in either direction, assuming returns are normally distributed.
While volatility is widely used, it has limitations. It treats upside and downside movements equally, even though most investors are primarily concerned about downside risk. The assumption of normally distributed returns doesn't always hold true, as financial markets often exhibit fat tails and skewness. Additionally, past volatility may not predict future volatility accurately, especially during regime changes or unprecedented market events.
For a more nuanced view of risk, consider using this calculator alongside the Sortino Ratio Calculator (which focuses on downside deviation) or the Monte Carlo Investment Simulator for probability-based scenario analysis. Volatility should be just one component of a comprehensive risk assessment framework.