Z-Score Calculator
Z-score for a value against a mean.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Z-Score Calculator
How to use this tool
- Enter your values in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.
Worked example
With a value of 85, a mean of 70 and a standard deviation of 10, the z-score is (85 - 70) / 10 = 1.5.
What this tool does not do / Limits
This is plain arithmetic on the numbers entered. It does not say whether the data is normally distributed and it cannot turn a z-score into a percentile without a distribution assumption.
Frequently asked questions
What does a z-score of 1.5 mean?
The value sits 1.5 standard deviations above the mean. A negative score would mean below the mean.
Can I get a percentile from this?
Only if you also assume a distribution, such as the normal distribution, which this tool does not assume.
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