Annualized Volatility

Volatility is the degree of variation of returns over time as measured by the standard deviation of returns. Monthly volatility is computed using the standard deviation of monthly returns over the given time period and annualized volatility is calculated by multiplying the monthly volatility by the square root of 12. This formula makes the assumption that returns follow a Gaussian (normal) distribution and so variance is proportional to time and standard deviation is proportional to the square root of time. 

On the statistics page you can also see Annualized Volatility for the last three years and the last five years.