z = 1.5
Z-score Calculator
Use this free z-score calculator to standardize a value from its mean and standard deviation, see whether it is above or below average, and estimate percentile.
Formula steps Examples included Copy results Private history
Z-score1.5
- Percentile
- 93.3192769023%
- Distance
- Above mean
- Mean
- 70
How to use the z-score calculator
- Enter the value, mean, and standard deviation.
- Press Calculate z-score to standardize the value.
- Review whether the value is above or below the mean and the approximate normal percentile.
- Use examples, recent answers, or copy the result while checking statistics work.
Common uses
Standardize a value using mean and standard deviation.
See how many standard deviations a value is above or below average.
Estimate a percentile under the standard normal curve.
Check statistics, normal distribution, and study examples.
Examples
z = 0
z = -1.5
Frequently asked questions
Quick answers about formulas, inputs, examples, result copying, and private in-browser history.
What is a z-score?
A z-score tells how many standard deviations a value is above or below the mean.
What formula does the calculator use?
It uses z = (x - mean) / standard deviation.
What does a negative z-score mean?
A negative z-score means the value is below the mean. A positive z-score means it is above the mean.
What does the percentile estimate mean?
The percentile estimates the area to the left of the z-score on a standard normal curve.
Can the standard deviation be zero?
No. A z-score divides by standard deviation, so the standard deviation must be greater than zero.
Is my z-score history private?
Yes. Recent z-score answers stay only in the current browser tab while you use the page. They are not sent to a server.
Related tools
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