Statistics calculator
Z-Score Calculator
Calculate z-score, approximate percentile, and distance from the mean.
Formula
Z-score
z = (value - mean) / standard deviation
A value of 85 with mean 70 and SD 10 has z = 1.5.
FAQs
What does a positive z-score mean?+
It means the value is above the mean by that many standard deviations.
Is the percentile exact?+
It is an approximation based on the standard normal distribution.
How does the Z-Score Calculator calculate the result?+
It uses the Z-score: z = (value - mean) / standard deviation. A value of 85 with mean 70 and SD 10 has z = 1.5.
What information do I need to use the Z-Score Calculator?+
Calculate z-score, approximate percentile, and distance from the mean.
How accurate is the Z-Score Calculator?+
Z-Score Calculator applies the formula and assumptions shown on this page. Results may be rounded for readability, so verify changing rates, thresholds, medical guidance, or legal rules with the cited source or a qualified professional.
What should I check before using the Z-Score Calculator result?+
Check that the units, dates, rates, and assumptions match your situation. Change one input at a time to understand which values have the largest effect on the result.
Statistics guide
How to use the Z-Score Calculator
Calculate z-score, approximate percentile, and distance from the mean. The page also explains the z-score and shows a practical example: A value of 85 with mean 70 and SD 10 has z = 1.5.
- 1
Enter your details
Enter the mean, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the z-score: z = (value - mean) / standard deviation.
- 3
Compare scenarios
Change one or more inputs to see how they affect the z-Score Calculator result before you use the estimate.
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