Probability Calculator

Calculate the probability of a single event, its complement, or the probability involving two events.

Probability = Favorable Outcomes / Total Outcomes

Favorable Outcomes

Total Possible Outcomes

Complement Probability = 1 - P(A)

Probability of Event A

For independent events: P(A and B) = P(A) x P(B)

Probability of A

Probability of B

P(A or B) = P(A) + P(B) - P(A and B)

Probability of A

Probability of B

P(A and B)

Result

Probability -

Decimal -

Percentage -

Single Event

P(A) = Favorable Outcomes / Total Outcomes

Complement

P(not A) = 1 - P(A)

Independent Events

P(A and B) = P(A) x P(B)

Either Event

P(A or B) = P(A) + P(B) - P(A and B)

A probability must always be between 0 and 1, or between 0% and 100%.