Z-Score Calculator
Math ToolsZ-score, percentile and p-value
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All history →Z-Score Calculator — at a glance
See how far a value is from average, in standard deviations.
x = 85
mean 70, SD 10
Calculate Z-Score
1.500
93.3 percentile
How to use it — step by step
A value, the mean and the standard deviation.
1
Enter your numbers
Fill in the fields — sensible example values are already filled in.
2
Pick your options
Choose any dropdowns or switches that apply to your case.
3
Calculate Z-Score
Press the button. The result is created instantly on your device.
4
Read the answer
The main answer is shown big at the top, with details below it.
Pro tips
Small things that make the result better.
✦A z-score of 0 means exactly average.
✦About 95% of values lie within ±2 standard deviations.
✦Scores beyond ±3 are very rare in a normal distribution.
Quick facts
Freeno signup, no limit
Instantresult in a moment
Privatenothing is uploaded
Any devicephone, tablet or PC
Frequently Asked Questions
What is the formula?+
z = (x − mean) ÷ standard deviation.
Is the percentile exact?+
It is accurate to about 6 decimal places using a standard approximation of the normal curve.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
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