How betting odds work: what they are and how to use them

The odds are a ratio of probabilities; an odds ratio is a ratio of odds, that is, a ratio of ratios of probabilities. In probability theory and statistics, odds and similar ratios may be more natural or more convenient than probabilities. Odds can also be expressed as a number, by dividing the terms in the ratio—in this case it is unique (different fractions can represent the same rational number). For example, «odds of a weekend are 2 to 5», while «chances of a weekend are 2 in 7». Implied by this definition is the fact that the probability of an event is given by the ratio of favourable outcomes to the total number of possible outcomes. If k is any positive number then X to Y is the same as kX to kY, and similarly if «to» is replaced with «in» or «for».

We cover the NHL, the SHL in Sweden and the KHL among many hockey leagues, with prices on single games and on the outright winners. Basketball goes from NBA odds and the EuroLeague to domestic leagues such as the Super Lig in Turkey and the LNB in France, with prices on single games and on the outright winners. Before a bet, check the archived results and historical odds of the teams or players involved, across leagues and tournaments worldwide.

For instance, if the line is 220.5 in an NBA game, you’d bet on whether the teams’ combined score will be over 220 or under 220.5. Totals bets, also known as Over/Under bets, focus on the combined score of both teams rather than who wins. Point spread bets are all about leveling the playing field between teams, making any game more exciting.

Because of the many factors involved, it non gamstop sports betting is impossible to calculate exact probability in sports betting. In betting terms, probability is odds expressed as a percentage. Moneyline odds use $100 as the evens line, with either positive or negative outcomes. If you’d like a bit more guidance, we have a full guide on how fractional odds work in betting. You may also see odds expressed with the lowest number first e.g. 1/2 or 2/7.

Higher numbers indicate higher potential payouts, while lower numbers signify favorites and lower returns relative to the stake. The key to understanding decimal odds is that they directly represent the total return. Decimal odds are the simplest format for many bettors, popular across Europe, Canada, and Australia. When novice bettors first realize that -125, 1.80 and 4/5 all represent the same probability, it can make them dizzy – but we’re here to lay it all out clearly.

Multiplying these probabilities by 100% gives the percentage. When probability is expressed as a number between 0 and 1, the relationships between probability p and odds are as follows. When Moneyline odds are quoted as a positive number +X, it means that a wager pays X to 100.

The total of these three percentages is 100%, thus representing a fair ‘book’. In a 3-horse race, for example, the true probabilities of each of the horses winning based on their relative abilities may be 50%, 40% and 10%. In formulating the odds to display the bookmaker will have included a profit margin which effectively means that the payout to a successful bettor is less than that represented by the true chance of the event occurring.

Once you understand betting odds and the differences between them, reading them becomes easy. Fractions were traditionally used to bet on horse racing and were most popular in high street betting shops in the UK, before the advent of internet gambling. Betting odds are usually expressed either as fractions (e.g. ‘3/1’) or as decimals (e.g. 4.0). All of these have different possibilities, probabilities, chances – or odds – of happening.