Statistics Calculators

Z-Score Calculator

Calculate the z-score of a value — how many standard deviations it is above or below the mean.

Z-score —

About the Z-Score Calculator

A z-score (standard score) tells you how many standard deviations a data point is above or below the mean of its dataset. A z-score of 0 means the value equals the mean; positive values are above the mean, negative values are below.

Formula: z = (x − μ) ÷ σ

Z-scores let you compare values from different distributions on a common scale, and are the basis for standard normal distribution tables and confidence intervals.