Fact checked by Michael Rosenston Reviewed by Somer Anderson Standard Deviation vs. Variance: An Overview Standard deviation and variance are two basic mathematical concepts that have an important ...

The standard deviation is calculated by finding the mean, calculating the variance and taking the square root of the variance.

Calculating rate of return and standard deviation is more challenging if you have no past data to rely on. If you are planning to open a restaurant, you cannot use past data.

The calculation of realized volatility is relatively straightforward, typically using the standard deviation of returns over a set period, often daily, weekly, or monthly.

Find out what portfolio variance is, the formula to calculate portfolio variance, and how to calculate the variance of a portfolio containing two assets.