← Math & statistics

Distribution calculator (Binomial / Poisson / Student's t / Chi-square)

Compute PMF/PDF, CDF, quantiles, and exact confidence intervals with step-by-step explanations, graphs, CSV, LaTeX, and shareable URLs.

Regularized beta/gamma routines keep the CDFs stable, Acklam’s normal approximation plus Newton steps invert the quantiles, and exact Clopper–Pearson / chi-square intervals help you justify estimates in class.

Other languages ja | en | zh-CN | zh-TW | zh-HK | es | es-419 | es-MX | pt-BR | pt-PT | id | vi | ko | fr | de | it | ru-RU | hi-IN | bn-BD | th-TH | fil-PH | fa-IR | nl-NL | he-IL | cs-CZ

Inputs & Modes

Parameters

Result

How it’s calculated

    Visualization

    Discrete distributions render as bars with highlighted tails; continuous ones display the PDF curve plus shaded regions or quantile markers.

    Teacher notes

    FAQ

    How are CDFs and quantiles computed?

    Binomial CDFs use regularized incomplete beta, Poisson and chi-square rely on regularized gamma, and Student’s t maps to beta functions combined with Newton or bisection for robust inversion.

    What can I do with the exact intervals?

    The Clopper–Pearson interval for p and the chi-square based interval for λ quantify uncertainty exactly, so you can document precision requirements in labs or assessments.

    How it’s calculated

    • Evaluates PDF/CDF/quantiles for common distributions using numerically stable formulas.
    • Parameters are validated (support, shape) and results are rounded for display only.
    • The shareable URL keeps the distribution, parameters and query type.