Odds (Probability)

What are Odds?

Odds are a numerical expression, typically represented by a pair of numbers, used both in gambling and statistics as a way of understanding probability. For example, in statistics, odds represent the likelihood that an event will occur. It is important to note, however, that odds to not directly represent probability of an event occurring, but rather the ratio of events to non-events in total.

Odds vs. Probability

A good way to understand the difference between odds and probability is to imagine rolling a die and hoping to land on a two. The odds of rolling the two are 1 to 5. One representing the chance of landing on the two, and five representing the alternative possibilities of landing on one of the other sides. The probability of rolling a two with the die is 1/6, as there are six total possible numbers that could be rolled.

Applications of Odds

Odds are frequently used to represent chance and probability in both statistics and gambling. The terms "odds on," "odds against," and "even odds" have been adopted colloquially by English speakers, with references to odds dating back to the 1500s.


Odds are frequently relied upon in gambling and used by gamblers to understand their chances of winning. For example, a gambler may refer to equal chances of winning and losing as "even money," simply representing 1 to 1 odds. Traditional examples of odds in gambling include a coin toss and heads or tails.

Odds in Machine Learning

Machine learning applies the principles of odds and probability theory in making decisions. Odds help inform the predictive accuracy of neural networks, improving things like sports predictions to better help club owners and managers price their bets.