About the Probability Calculator
Calculate AND, OR, and conditional probabilities, plus Bayes' theorem, for two events.
What it is
The Probability Calculator computes every common probability relationship between two events from a small set of inputs: the joint (AND) probability, the union (OR) probability, and both conditional probabilities, including Bayes' theorem. An independent-events toggle auto-derives the joint probability when the events don't influence each other, and input consistency is checked so impossible combinations are flagged rather than silently accepted.
Features
AND / OR / conditional
All the standard two-event probability relationships computed at once.
Bayes' theorem
Reverses a conditional probability, with the theorem shown explicitly.
Independent-events toggle
Auto-derives P(AโฉB) = P(A)รP(B) when events are independent.
Venn diagram
Visualizes exactly how the two events overlap.