Overview
What Is a Z-Score?
A z-score measures how many standard deviations a value is from the mean of a data set, showing its relative position.
Calculate the z-score of a value instantly.
A z-score measures how many standard deviations a value is from the mean of a data set, showing its relative position.
Useful for coursework involving normal distributions and standardized comparisons.
Input the specific data point.
Input these from your data set.
The result updates automatically.
Z = (Value - Mean) ÷ Standard Deviation
It means the value is 2 standard deviations above the mean.
It means the value is below the mean.
Values beyond ±2 or ±3 are often considered statistically unusual, depending on context.
Use our average calculator for mean and standard deviation calculator for standard deviation.
Comparing values across different distributions, identifying outliers, and standardized testing analysis.
Yes, this occurs when the value exactly equals the mean.
No, calculations happen entirely in your browser.
Z-scores are most meaningfully interpreted for normally distributed data, though the calculation itself works for any data.
Yes, completely free with no sign-up required.