About the Binomial Distribution Calculator

Computes binomial probabilities from n and p, with a full distribution chart.

What it is

Enter n and p, choose exactly/at-most/at-least/between, and get the probability computed via the exact binomial PMF using a log-space Lanczos gamma function for numerical stability, alongside the mean, variance, and standard deviation.

Features

Four query types

Exactly, at most, at least, and between k1/k2.

Full PMF chart

Bar chart of every outcome, with the queried region highlighted.

Mean/variance/SD

Computed alongside every probability.

Exact combinatorics

Log-space computation avoids precision loss for larger n.

Ready to use it?

Free, no sign-up required.

Open the Binomial Distribution Calculator