Standard score z=(x−μ)/σ with an approximate normal-distribution percentile.. Z-Score Calculator is a free online tool from the ToolsRift Math Calculators collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Enter the value x, the mean μ and the standard deviation σ, and the calculator returns the z-score and its approximate percentile.
The number of standard deviations a value lies from the mean: z = (x − μ) / σ.
It means the value is below the mean; a positive z-score means it is above the mean.
An approximate percentage of a normal distribution that falls below your value, derived from the z-score.