Probability Calculator
Calculate probability of single events, combined events (AND/OR), permutations, and combinations.
Inputs
%
%
Results
Result
50
Complement (NOT)50%
Odds1 in 2
At Least Once in N Trials99.9%
How to Use This Calculator
- For a single event, enter the number of favorable outcomes and the total number of equally likely outcomes.
- Probability = favorable / total; the result is displayed as a decimal, fraction, and percentage.
- For combined events, enter probabilities of event A and B, then choose AND (intersection) or OR (union).
- P(A and B) = P(A) × P(B) for independent events; P(A or B) = P(A) + P(B) − P(A and B).
- The pie chart shows the probability vs. complement (1 − P) split visually.
- All probabilities must be between 0 and 1 (or 0% and 100%); total outcomes must be at least 1.
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