Z-SCORE CALCULATOR
Standardize your data and explore the normal distribution. Compute z-scores from raw values and determine precise probabilities with our professional statistical toolset.
Raw Score to Z-Score
Standardize a specific data point relative to its population.
Enter parameters to see standardization
Z-Score & Probability Converter
Bidirectional conversion between z-scores and cumulative probabilities.
Fill any field to see statistical relationship
Probability Between Z-Scores
Find the area under the curve between any two z-points.
Enter bounds to visualize distribution area
What is a Z-Score?
A z-score, or standard score, is a statistical measurement that describes a value's relationship to the mean of a group of values. It is measured in terms of standard deviations from the mean.
The Core Formula
Standard Score Calculation
- • x: The raw score (data point)
- • μ: The population mean
- • σ: The population standard deviation
Why Use Z-Scores?
Z-scores allow statisticians to compare scores from different distributions. For example, you can compare a score on an SAT test to a score on an ACT test by standardizing both to their respective normal distributions.
A z-score of 0 indicates the score is exactly the mean, while a z-score of 1.0 indicates the score is one standard deviation above the mean.