Z-Score Calculator
Calculate probabilities and quantiles for the standard normal distribution (mean 0, std 1) with z-score interpretation.
A z-score expresses how many standard deviations a value is from the mean. This calculator uses the standard normal distribution to map z-values to cumulative probabilities and vice versa.
Use it for hypothesis testing, confidence intervals, and quick percentile conversion when data are standardized.
Launch the Normal Distribution workspace to plot the curve, inspect PDF/CDF behavior, and compute quantiles and interval probabilities.
Open Interactive Tail RiskHow is z-score related to normal distribution?
Z is a normalized variable from a normal distribution with mean 0 and standard deviation 1.
How do I read P(Z ≤ z)?
Use the CDF chart or quantile controls; the CDF directly reports cumulative probability up to z.
Can I get two-tailed probabilities?
Yes, use symmetry and combine tail areas; for ±z, two-tailed probability is 2·P(Z > |z|).