How does rounding work?
Probabilities are displayed with up to four decimal places, but calculations use double precision internally.
Step-by-step walkthrough
Binomial Probability Calculator Guide
Use this companion guide beside the interactive calculator to make sure you understand the “why” behind every click. Each section includes the classroom explanation, student-friendly language, and quick practice prompts.
Before you start
Collect the data points listed below and double-check their units. Keeping an organized “givens” list is one of the fastest ways to reduce math errors and impress exam graders.
- binomial distribution
- probability
- discrete
Detailed procedure
Step 1
Provide the number of trials n and success probability p.
Step 2
Enter the number of successes k and choose exact, at-most, or at-least mode.
Step 3
Read the probability, expected value, and variance.
Teaching & troubleshooting tips
Is cumulative probability inclusive?
Yes. P(X ≤ k) includes the k term, and P(X ≥ k) includes k as well.