Free Complement Probability Calculator
Calculate the probability that an event does NOT occur, which is 1 minus the probability of the event.
P(Not Event)
0.650000
Complement (%)65.0000
Odds Against1.8571
P(Not Event) vs P(Event)
How to Calculate Complement Probability
Formula
P(A') = 1 - P(A)
The complement of an event A includes all outcomes where A does not happen. Since all probabilities must sum to 1, the complement is simply 1 minus the event probability. This is often useful for "at least one" problems where computing the direct probability is complex.
Example Calculation
The probability of rain is 0.35. What is the probability it does not rain?
- 01P(rain) = 0.35
- 02P(no rain) = 1 - 0.35 = 0.65
- 03As a percentage: 65%
- 04Odds against rain: 0.65 / 0.35 ≈ 1.857
Frequently Asked Questions
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