Statistics

Z-Score Calculator

A z-score tells you how unusual a value is. A z of 0 is exactly average; 2 means two standard deviations above the mean, which is higher than about 97.7% of values in a normal distribution.

Your result will appear here.

How it's calculated

Subtract the mean from the value and divide by the standard deviation. The percentages come from the standard normal distribution, so they assume your data is roughly bell-shaped.

z = (x − μ) ÷ σ

How to do it in Excel

=STANDARDIZE(85, 70, 10): Returns the z-score, 1.5.
=NORM.S.DIST(1.5, TRUE): Share of values below that z-score.