Probability Calculator

Probability is the chance that the given event will occur. Use this online probability calculator to calculate the single and multiple event probability based on number of possible outcomes and events occurred.

Simple Probability Calculator

Single Event Probability

Result



Multiple Event Probability

Result

Probability is the chance that the given event will occur. Use this online probability calculator to calculate the single and multiple event probability based on number of possible outcomes and events occurred.

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Probability is about finding the likelihood of some events to happen. It is expressed as a number between 0 and 1. Here 1 is considered as certainty (True) and 0 is taken as impossibility (False). Use our online probability calculator to find the single and multiple event probability with the single click. The best example of probability would be tossing a coin, where the probability of resulting in head is .5 and its similar for tossing the tails. It can be calculated by dividing the number of possible occurrence by the total number of options. The higher the probability of an event, the more certain that the event will occur. Probabilities in general describes the underlying mechanics and regularities of complex systems. Make use of probability calculators to solve the probability problems with ease.

Single Event Probability Formula :

Probability of event A that occurs P(A) = n(A) / n(S). Probability of event A that does not occur P(A') = 1 - P(A).

Multiple Event Probability Formula :

P(A) = n(A) / n(S). P(A') = 1 - P(A). P(B) = n(B) / n(S). P(B') = 1 - P(B). Probability that both the events occur P(A ∩ B) = P(A) x P(B). Probability that either of event occurs P(A ∪ B) = P(A) + P(B) - P(A ∩ B). Conditional Probability P(A | B) = P(A ∩ B) / P(B). Where, n(A) - Number of Occurrence in Event A, n(B) - Number of Occurrence in Event B, n(S) - Total Number of Possible Outcomes.

Example

Single Event Probability

Find single event probability, given n(s) = 20, P(A) = 13

Step 1 : To find P(A)
         P(A) = 13 / 20 = 0.65

Step 2 : To find P(A')
          P(A') = 1 - 0.65 = 0.35

Multiple Event Probability

Find multiple event probability, given n(s) = 10, n(A) = 8 and n(B) = 2

Step 1 : To find P(A)
         P(A) = 8 / 10 = 0.8

Step 2 : To find P(A')
          P(A') = 1 - 0.8 = 0.2

Step 3 : To find P(B)
         P(B) = 2 / 10 = 0.2

Step 4 : To find P(B')
          P(B') = 1 - 0.2 = 0.8

Step 5 : To find P(A ∩ B)
         P(A ∩ B) = 0.8 *0.2 = 0.16

Step 6 : To find P(A ∪ B)
         P(A ∪ B) = ( 0.8 + 0.2 ) - 0.16 = 0.84

Step 7 : To find P(A | B)
         P(A | B) = 0.16 / 0.2 = 0.8

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