Probability & Odds Calculator

Calculate independent, compound, joint, and conditional probabilities, or convert between probabilities and odds ratios.

Calculated Probabilities

P(A AND B)0.200000 (20.00%)
P(A OR B)0.700000 (70.00%)
P(Not A) / P(Not B)0.5000 / 0.6000
P(Neither)0.300000

Probability Equations & Explanations:

P(A') = 1 - P(A) = 1 - 0.5000 = 0.5000
P(B') = 1 - P(B) = 1 - 0.4000 = 0.6000
P(A ∩ B) = P(A) × P(B) = 0.5000 × 0.4000 = 0.2000
P(A ∪ B) = P(A) + P(B) - P(A ∩ B) = 0.5000 + 0.4000 - 0.2000 = 0.7000
P(Neither) = P(A') × P(B') = 0.5000 × 0.6000 = 0.3000

Frequently Asked Questions

What are independent events?

Two events are independent if the occurrence of one does not affect the probability of the occurrence of the other. E.g., flipping a coin twice.

How do odds relate to probability?

If the probability of an event is P, the odds in favor are P / (1 - P), usually expressed as a ratio A:B where A/B = P/(1-P).