Z-Score Calculator

You can use this Z-Score Calculator to calculate the standard normal score (z-score) based on the raw score value, the population mean, and the standard deviation of the population.

How to use the calculator

  1. Enter the raw score value
  2. Enter the mean, standard deviation, and click the "Calculate" button to see the results.
Z-Score Calculator

Z-Score from P-Value Calculator

Use this online tool to calculate the z-score for a given p-value.

Z-Score Formula

The Z-Score Calculator uses the following formula:

z = (x - μ) / σ


z is the standard score or Z-score,

x is the raw score to be standardized,

μ is the mean of the population,

σ is the standard deviation of the population.

Z-Score Calculation Example

The mean of a dataset is 20 and the standard deviation is 7. Find the z-score for a value of 6.

x = 6, μ = 20, σ = 7

z = (6 - 20) / 7

z = -14 / 7 = -2

z = -2

Reference: Norman, G. R. and Streiner, D. L., Biostatistics: The Bare Essentials. 2nd edition. London: B.C. Decker, 2000.

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