Calculate the probability of two events occurring together or separately, and the binomial chance of exactly k successes in n trials. Free, instant and easy to read.

Two events

Enter a percentage (e.g. 50) or a decimal between 0 and 1.

Binomial — exactly k successes

P(A and B)
P(A or B)
P(not A)
P(exactly k)
Independent events assume one outcome does not affect the other. Mutually exclusive events cannot both happen, so P(A and B) is 0. The binomial result is the chance of exactly k successes in n independent trials.

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