Convert a raw value into a z score, the number of standard deviations it lies above or below the mean. Enter the value, the population mean, and the standard deviation, and the tool returns the z score plus the percentile that value falls at under a normal distribution. The z score is simply the value minus the mean divided by the standard deviation, so a positive result is above average and a negative result is below. Because the tool also runs the raw value through the normal cumulative distribution, you can see at a glance whether a data point is common or an outlier. Standardizing this way lets you compare scores from different scales, such as test results graded on different curves. Everything is computed locally in your browser, so your numbers never leave the page.
It counts how many standard deviations a value sits above or below the mean, so a z-score of 2 is two standard deviations above average.
Subtract the mean from the value and divide by the standard deviation.
The percentile shows the percentage of a normal distribution that falls below your value based on its z-score.
Convert a raw value into a z score, the number of standard deviations it lies above or below the mean. Enter the value, the population mean, and the standard deviation, and the tool returns the z score plus the percentile that value falls at under a normal distribution.
Yes. Z-Score Calculator is completely free, with no sign-up and no usage limits.
Yes. Z-Score Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Z-Score Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.