How this calculator works
Enter the values for first value, second value and review the units before calculating.
Formula / method
z = (x − μ) ÷ σ
Worked example
A value of 75 with mean 60 and standard deviation 10 has z = 1.5.
Assumptions and limitations
The standard deviation is positive and the distribution is suitable for standardized comparison.
A z-score does not prove normality or statistical significance.