Z-Score Calculator
Find how many standard deviations a value is from the mean, plus its approximate percentile.
How to use
Enter value, mean and standard deviation.
Formula
z = (x - μ) / σ; percentile via normal CDF approximation.
Examples
- x=110, μ=100, σ=15 → z=0.67, ~74.8th percentile
Important notes
Assumes normal distribution.
Frequently asked questions
What is a z-score?
Standard deviations from the mean.