Bayes' Theorem Calculator
Update a probability with new evidence using Bayes' theorem — prior, true-positive rate and false-positive rate, free online.
About this calculator
P(A|B) = P(B|A)·P(A) ÷ P(B), where P(B) = P(B|A)·P(A) + P(B|¬A)·P(¬A). In diagnostic testing, A is having the condition, B a positive result, P(B|A) the sensitivity and P(B|¬A) the false-positive rate.