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Statistics Calculators

Conditional Probability Calculator

Calculate the conditional probability P(A|B) — the probability of event A occurring given that event B has already occurred.

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P(A|B)
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About the Conditional Probability Calculator

Conditional probability measures how likely an event is once you already know another event has happened. It narrows the "universe" of possible outcomes down to just those where B is true, then asks what share of those also include A.

Formula: P(A|B) = P(A and B) ÷ P(B)

Conditional probability is the building block behind Bayes' theorem and is used constantly in medical testing, risk modeling, and any situation where new information should change your estimate of what's likely.

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