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.ss
Probability Calculator Formula / Calculation
 
Single Event Probability Formula
Possible Outcomes = 65
Events Occured = 55
P ( A )
= Events Occured / Possible Outcomes = 55 / 65 = 0.85
P ( A' )
= 1 - P ( A ) = 1 - 0.85 =
0.15
 
Multiple Event Probability Formula
Possible Outcomes = 16
Event Occurs in A = 8
Event Occurs in B = 12
P ( A )
= Event Occurs in A / Possible Outcomes = 8 / 16 =
0.5
P ( A' )
= 1 - P ( A ) = 1 - 0.5 =
0.5
P ( B )
= Event Occurs in B / Possible Outcomes = 12 / 16 =
0.75
P ( B' )
= 1 - p ( B' ) = 1 - 0.75 =
0.25
P ( A ∩ B )
= P ( A ) * P ( B ) = 0.5 * 0.75 =
0.38
P ( A ∪ B )
= P ( A ) + P ( B ) - P ( A ∩ B ) = 0.5 + 0.75 - 0.38 =
0.88
P ( A | B )
= P ( A ∩ B ) / P ( B ) = 0.38 / 0.75 =
0.50