Statistics & probability
Two-event probability calculator
Work out union, neither and conditional probabilities from an intersection.
A clear answer. Here’s how.
Requires max(0,P(A)+P(B)−1) ≤ P(A∩B) ≤ min(P(A),P(B)). Computes the union, neither, A only, B only and both conditional probabilities. A conditional probability with a zero conditioning-event probability is undefined. No independence assumption is made.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- P(A)
- 0.4
- P(B)
- 0.3
- P(A and B)
- 0.1
Example result
- P(A or B)
- 0.6
- P(neither)
- 0.4
- P(A only)
- 0.3
- P(B only)
- 0.2
- P(A | B)
- 0.333333333333
- P(B | A)
- 0.25