Normal Distribution Calculator

Use this Normal Distribution Calculator to find probabilities and visualize areas under the normal curve. In the calculator, enter an Observed Value (X), Population Mean (μ), and Standard Deviation (σ). It displays the probability that a value is less than X, greater than X, between the mean and X, within a symmetric range around the mean, and outside that range. The calculator also includes clear, shaded graphs for each probability and a step-by-step breakdown of the z-score calculation.

Below the Normal Distribution Calculator, you’ll find additional resources to help you interpret the results. See all my Statistical Calculators!

Learn more about the normal distribution in my articles about the Normal Distribution and using Z-scores. Additionally, my article about using Probability Distribution Functions (like the normal distribution) will help you interpret the Normal Distribution Calculator results.