This calculator finds the chance of an event for anyone checking odds in games, surveys, forecasts, or basic statistics.
The interactive probability calculator loads right here. If it hasn't appeared, refresh the page.
Enter the number of favorable outcomes and the total number of equally likely outcomes. For combined events, specify whether both events must happen or at least one may happen, and whether the events are independent.
A single event's probability is P(A) = favorable outcomes / total outcomes. For independent events, P(A and B) = P(A) × P(B); for mutually exclusive events, P(A or B) = P(A) + P(B); and the complement is P(not A) = 1 - P(A).
A standard deck has 4 aces among 52 cards, so the probability of drawing an ace is 4 / 52 = 0.0769, or 7.69%. The chance of not drawing an ace is 1 - 0.0769 = 0.9231, or 92.31%.
Probability compares favorable outcomes with all outcomes. Odds in favor compare favorable outcomes with unfavorable outcomes, so a probability of 1/4 corresponds to odds of 1 to 3.
No. A valid probability ranges from 0 to 1, or from 0% to 100%; anything outside that range means the inputs or method need another look.
More from DoesWhat: free calculators · emoji meanings · quick answers · the DoesWhat blog