📐 Math
Probability Calculator
Calculate the probability of single and multiple events occurring. Supports finding the probability of events happening together (intersection), at least one happening (union), or dependent events.
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Formula
P(A and B) = P(A) × P(B) [Independent] | P(A or B) = P(A) + P(B) - P(A and B)P(A)- Probability of Event A occurring
P(B)- Probability of Event B occurring
Example
Rolling a Die and Flipping a Coin
Find the probability of rolling a 6 on a fair six-sided die AND flipping Heads on a fair coin.
- Find P(A), rolling a 6: 1/6 ≈ 0.1667.
- Find P(B), flipping Heads: 1/2 = 0.5.
- Because these events are independent, multiply them together.
- P(A and B) = (1/6) × (1/2) = 1/12.
- Result: 1/12 or approx 8.33%.
Frequently Asked Questions
Mutually exclusive events cannot happen at the same time (e.g., rolling a 2 and a 3 on a single die roll). For these, P(A and B) is 0, so the 'OR' formula simplifies to P(A) + P(B).