Probability

Single and combined event probabilities.

Enter values

P(A)

P(B)

—

independent: P(A∩B) = P(A)·P(B); P(A∪B) = P(A)+P(B)−P(A∩B)

All calculations run locally in your browser and update instantly as you type.

Does this assume independence?+

Yes — the "and" rule shown multiplies probabilities, which is valid only when the two events do not affect each other.

All calculations run locally in your browser. Nothing you type is sent to a server.