Binomial Probability Calculator

Formula

C(n,k)p^k(1−p)^(n−k)

Worked example

n=5,k=2,p=.5 — 0.3125

Quick answer

What does the Binomial Probability Calculator do?

Calculate probability of exactly k successes in n independent trials.

What is the Binomial Probability Calculator?

Calculate probability of exactly k successes in n independent trials. Use it when you have the required inputs and want a deterministic, repeatable result with the calculation method visible.

How to use this calculator

Enter the values requested by the tool, keep units and time periods consistent, resolve any validation message, calculate, then review the primary answer together with the displayed formula and supporting values.

Formula and method

This calculator uses the deterministic formula C(n,k)p^k(1−p)^(n−k). Enter the required values, then review the displayed substitution and result breakdown to verify the calculation.

Worked example

n=5,k=2,p=.5 0.3125

Common mistakes to avoid

Check units, decimal points, percentages, signs, date/time order, selector choices, and rounding. For important decisions, verify the result against an independent source or qualified professional when appropriate.