Math Calculators
Z-Score Calculator
Find how many standard deviations from the mean.
FreeNo sign-upWorks in your browser
Enter details
Result
Z-score
1.5
z = (x − μ) / σ
About the Z-Score Calculator
A z-score tells you how many standard deviations a value sits above or below the mean. Enter the value, the mean, and the standard deviation and the calculator returns the z-score using z = (x − μ) ÷ σ. It's a core statistics tool for standardizing data, comparing scores, and finding probabilities on the normal curve.
How to use the Z-Score Calculator
- 1Enter your value, mean, and standard deviation.
- 2Read the result instantly — it recalculates as you type.
- 3Adjust the numbers to model different scenarios.
Frequently asked questions
What is a z-score?
The number of standard deviations a data point is from the mean. z = 0 is exactly average; z = 2 is two standard deviations above.
What is a good z-score?
It depends on context. Roughly 95% of normally distributed data falls between z = −1.96 and z = +1.96.