Binomial Distribution Calculator

Added 2026-08-29

Calculate exact, cumulative and upper-tail binomial probabilities plus mean and standard deviation.

✓ Runs locally in your browser✓ No account or dataset upload required✓ Effect sizes / uncertainty shown where appropriate

Trials n

Successes k

Success probability p

P(X = k)

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P(X ≤ k)

—

P(X ≥ k)

—

Mean

—

Statistical output is a calculation aid. Check assumptions, study design and reporting requirements before drawing scientific conclusions.

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About this tool

Calculate exact, cumulative and upper-tail binomial probabilities plus mean and standard deviation.

Common uses

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How it works

1Enter or paste the requested sample values, summary inputs or contingency data.
2Choose the method, confidence level or test options when available, then run the calculation.
3Review the estimate/test statistic together with p-value, confidence interval, effect size and method notes where available.

Does this statistics calculation upload my data?

No. Entered values are processed locally in your browser with JavaScript.

Should I interpret statistical significance by itself?

No. Review effect size, confidence intervals, study design, assumptions, sampling and multiplicity together with the p-value.