Probability Calculator

Calculate basic probability, combined event probability (union, intersection, conditional), and binomial distribution probabilities.

Type

P(A) = Favorable outcomes / Total outcomes

P(A)
0.3
30%
P(not A)
0.7
70%
Odds for A
3 : 7

Results

PropertyValue
Favorable outcomes3
Total outcomes10
P(A)0.3 = 30%
P(not A) = P(A')0.7 = 70%
Odds for A3 : 7
Fraction3/10

Key Formulas

RuleFormula
Addition ruleP(A∪B) = P(A)+P(B)−P(A∩B)
Multiplication (indep.)P(A∩B) = P(A)·P(B)
ConditionalP(A|B) = P(A∩B)/P(B)
ComplementP(A') = 1 − P(A)
BinomialC(n,k)·pᵏ·(1−p)ⁿ⁻ᵏ