Z-Score to Percentile Calculator
Convert a z-score to its percentile under the normal curve.
From z-score to percentile
A z-score says how many standard deviations a value is from the mean, and its percentile says what fraction of a normal distribution falls below it. This tool converts one to the other.
A z-score of 1.5 corresponds to about the 93rd percentile — 93% of the distribution lies below it. It uses an accurate approximation of the normal curve for reliable results.
Accurate and private
The calculation runs in your browser, so nothing you enter is uploaded.
Frequently Asked Questions
What does it convert?
A z-score into the percentile — the percentage of a normal distribution that falls below it.
How is it computed?
With an accurate approximation of the normal cumulative distribution using the error function.
What is a z-score of 0?
It sits at the mean, the 50th percentile, with half the distribution below it.
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