Probability

This probability calculator covers typical problems: classical probability, the addition and multiplication rules, conditional probability and the chance of at least one success.

Key formulas

P = m / n

P(A or B) = P(A) + P(B) − P(A and B)

P(A|B) = P(A and B) / P(B)

For independent events P(A and B) = P(A) · P(B); for mutually exclusive events P(A and B) = 0.