Calculate a z-score and see how far a value is from the mean in standard-deviation units.
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Averages, standard deviation, z-scores, normal distributions and probability calculations.
Enter the values requested above and select Calculate. Change any input to compare another scenario. The calculation runs locally in your browser and does not require an account.
A score of 85 in a distribution with mean 70 and standard deviation 10 has z = 1.5.
Calculate a z-score from a value, mean and standard deviation. The result is intended for quick estimates, checking arithmetic and comparing scenarios. When a result affects a contract, tax filing, medical decision, building-code requirement or other high-stakes situation, verify the result with the appropriate professional or authoritative source.
With value 85, mean 70, and standard deviation 10, the z-score is 1.5: (85−70) ÷ 10.
A positive z-score is above the mean; a negative one is below it.
The standard deviation must be positive, and z-scores alone do not establish that data follow a normal distribution.
Related tools: Triangle Area Calculator · Average Calculator
Calculate a z-score from a value, mean and standard deviation.
z = (x − mean) ÷ standard deviation.
Yes. ERICH Calculators is free to use and does not require an account.
A positive z-score is above the mean; a negative z-score is below it. A z-score of 2 means the value is two standard deviations above the mean.
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