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Volatility Index Calculator
Annualize a return series' standard deviation into a volatility percentage.
Annualized Volatility
28.57%
This calculator scales a periodic standard deviation of returns (e.g. daily) up to an annualized figure by multiplying by the square root of the number of periods in a year.
Annualized volatility is the standard way volatility is quoted and compared across assets and timeframes, making it easier to compare a stock's daily volatility to another asset's weekly or monthly volatility.
FAQ
Why multiply by the square root of periods?
Standard deviation scales with the square root of time under the assumption of independent, identically distributed returns — so annualizing daily volatility means multiplying by √252 (trading days in a year).
How is this different from VIX?
This calculates historical (realized) volatility from actual past returns, while VIX is a forward-looking, options-market-implied measure of expected future volatility.