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P
MATH

Probability Calculator

Solve Probability with a transparent method.

Choose a probability modelProbabilities are entered as decimals from 0 to 1.
5 options
PROBABILITY0.2

Probability of Two Events: Calculates two-event relationships, solves independent-event probabilities from any two known values, evaluates repeated independent events or exact binomial successes, and finds normal-distribution interval probability.

Probability of A: P(A)
0.4
Probability of B: P(B)
0.5
Probability of A NOT occurring: P(A′)
0.6
Probability of B NOT occurring: P(B′)
0.5
Probability of A and B both occurring: P(A∩B)
0.2
Probability that A or B or both occur: P(A∪B)
0.7
Probability that A or B occurs but not both: P(A△B)
0.5
Probability of neither A nor B occurring
0.3
Estimate based on the values shown
Formula checkedCalculates two-event relationships, solves independent-event probabilities from any two known values, evaluates repeated independent events or exact binomial successes, and finds normal-distribution interval probability.