Calculate event probability, P(A and B), P(A or B), and complement probability.
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Probability Calculator
Math
Inputs
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How to Use This Calculator
1
Enter P(A) as a decimal between 0 and 1 (e.g. 0.4 = 40% chance).
2
Optionally enter P(B) for combined probability calculations.
3
Select whether events are independent or mutually exclusive.
4
Click Calculate.
How It Works
P(A and B) for independent events = P(A) × P(B). P(A or B) = P(A) + P(B) − P(A and B). Mutually exclusive means P(A and B) = 0 so P(A or B) = P(A) + P(B).
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