Probability Calculator
Calculate probability for various scenarios including single events, multiple events, conditional probability, and complements
Probability Calculator
Probability Formulas
Basic Probability
P(Event) =
Favorable Outcomes
Total Outcomes
Multiple Events
P(A and B) = P(A) × P(B) [Independent]
P(A or B) = P(A) + P(B) [Mutually Exclusive]
P(A or B) = P(A) + P(B) - P(A and B) [General]
Conditional Probability
P(A|B) =
P(A and B)
P(B)
Bayes' Theorem
P(A|B) =
P(B|A) × P(A)
P(B)
Key Rules
Range: 0 ≤ P(Event) ≤ 1
Complement: P(A') = 1 - P(A)
Certain event: P(Event) = 1
Impossible event: P(Event) = 0
Frequently Asked Questions
Probability measures the likelihood of an event occurring, ranging from 0 (impossible) to 1 (certain). Basic probability = favorable outcomes ÷ total outcomes. For example, the probability of rolling a 6 on a die is 1/6 ≈ 0.167 or 16.7%.