Z-score calculator

Calculate z-scores, find probabilities from z-scores, and convert between raw scores and standard scores.

ValueMeanσ

What is a z-score?

A z-score measures how many standard deviations a value is from the mean: z = (x − μ) / σ. A z-score of 0 means the value equals the mean. ±1 captures ~68% of data, ±2 captures ~95%.