Bayes' Theorem Calculator

Update probability of (name of event A)
based on (name of event B)
P() = (prior probability of )
P(|) = (probability of given )
P(|¬) = (probability of given ¬)
P(|) = (posterior probability of given )
P(|¬) = (posterior probability of given ¬)

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Usage notes

Both decimal and % probabilities are supported.

This uses BigDecimal, not floating point math. It still loses bits with non-terminating decimals, though.

No warranty of any kind; see this fearsome no-warranty clause.