Bayes Theorem Calculator
Compute posterior probability from prior, sensitivity, and false positive rate.
Use this free online Bayes Theorem Calculator to compute posterior probability from prior, sensitivity, and false-positive/base-rate inputs. It is useful for analysis, reporting, coursework, and experiment planning when you need quick statistical evidence without building a spreadsheet. The form focuses on Prior P(A), Likelihood P(B|A), False positive P(B|¬A) and returns Bayes Inputs, Result, so you can move from input to answer without setting up a spreadsheet or custom script. Run one realistic example, adjust the inputs, and compare how the result changes before you copy or share it. Treat the result as a statistical aid: sample quality, independence, distribution assumptions, and context still determine whether the conclusion is valid.