Z-Score Calculator

    Calculate z-score and probability from normal distribution

    Formula

    Z = (X - μ) / σ

    Z-score measures how many standard deviations from the mean.

    Examples

    Score 85, mean 75, SD 10

    Z = 1.0, ~84th percentile.

    Frequently Asked Questions

    About Z-Score

    Calculate z-scores and approximate percentiles from normal distribution.