Binomial Distribution Calculator

Enter trials, success probability, and a success count to get exact, cumulative, upper-tail probability, mean, and standard deviation.

Trials (n)

Success probability (p)

Successes (k)

—P(X = k)

—P(X ≤ k)

—P(X ≥ k)

—Mean n·p

—Exact binomial probabilities are calculated client-side.

How to use this Binomial Distribution Calculator

Calculate exact binomial probabilities for repeated independent trials. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.