Skewness Calculator

About this calculator

Skewness measures how asymmetric a distribution is around its mean. The population skewness uses the third standardized moment (average of the cubed deviations from the mean, divided by the cubed standard deviation), while the sample skewness applies the Fisher-Pearson adjusted g₁ correction to reduce bias from working with a limited sample instead of the full population. A positive value means a longer right tail, negative means a longer left tail, and zero matches a symmetric distribution like the normal curve.

Data analysts and quants check skewness before applying statistical tests or models that assume normality, deciding whether a transform (like a log transform) is needed first, while quality engineers use it to spot asymmetric variation in a manufacturing process that a simple mean and standard deviation would miss.