Bayes Theorem Calculator

Connected statistics workflow

v10.85 connects descriptive statistics, probability models, distributions, confidence intervals, sample-size planning, hypothesis tests, correlation/regression, rank-based methods, and counting tools without replacing the established historical engines.

Interpret statistical results in context

Use plots and descriptive summaries before formal tests. Check the sampling/design assumptions that matter for the chosen method, report effect size and uncertainty where available, and avoid treating a threshold such as p < .05 as proof of importance, causation, or truth. Browser calculations are educational/planning utilities, not domain-specific professional advice.

How to use this Bayes Theorem Calculator

Enter a prior probability, P(B|A), and P(B|not A) to calculate P(A|B) and inspect the evidence decomposition.

What this tool calculates

Apply Bayes’ theorem to update an event probability from evidence.

Practical limits

The calculator uses textbook probability models. Independence is assumed only on pages that explicitly state it; real-world dependence or biased outcome mechanisms require a different model.