Z-Score Calculator

Use this z-score calculator to see how many standard deviations a value sits above or below the mean. It is useful for comparing test scores, measurements, KPIs, experiment results and other values where relative position matters more than the raw number alone.

Enter the observed value, the mean and the standard deviation to get the z-score, the distance from the mean and an approximate percentile. The percentile shown follows the usual normal-distribution interpretation, which makes the tool practical for statistics homework, performance reviews, research and basic data analysis.

A result close to zero means the value is near the average. A larger positive z-score means the value is further above the mean, while a more negative one means it is further below. That gives you a fast way to judge whether a result looks typical, strong, weak or unusually far from the center.