Joint Probability Calculator

Find P(A and B) and P(A or B) for independent events.

P(A and B) (%) 20

P(A or B) (%) 70

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

Step-by-step with your numbers:

1. Values used:

2. P(A) = 50 %

3. P(B) = 40 %

5. P(A and B) = (50 / 100) x 40 = 0.5 x 40 = 20%

6. P(A or B) = 70%

Did we solve your problem today?

Combine the probabilities of two independent events.

The math behind it

For independent events: P(A and B) = P(A)×P(B); P(A or B) = P(A)+P(B)−P(A and B).

50% & 40% → AND 20%, OR 70%.

Dependent events?

Use conditional probability instead — they're not independent.