How betting odds work: what they are and how to use them
Since these bets can be made months in advance, they offer a chance for big payouts, especially when backing underdogs. Instead of betting on a single game, you’re predicting outcomes like who will win the NBA championship, MVP award, or a division title. Bettors predict whether the total points scored will be above or below a set number. For example, if a team is -5.5, they need to win by 6 or more points to win the bet. Instead of just picking a winner, you’re betting on whether a team can “cover the spread,” meaning they either win by a certain margin or avoid losing by too much.
In tennis we follow the ATP and WTA tours every week, the Challenger and ITF events in between and the four Grand Slams, from the Australian Open to Wimbledon and the US Open. For beginners, our bet calculator shows the payout of a bet, for a single or an accumulator, in decimal, fractional or American odds. Enter how much you want to wager in total to see the stake for each outcome and the resulting profit. Our sure bets page shows a way to cover every outcome of a match across different bookmakers so that the combined odds return a profit, as long as the prices are still available when you place the bets. Our real-time data updates live scores as soon as a goal is scored, a point is won or a basket is made, and with live odds available for matches in-play, you can compare prices during a match and before it.
However, in more variable situations, such as a multi-runner horse race or a football match between two unequally matched teams, betting ”at odds” provides the possibility to take the respective likelihoods of the possible outcomes into account. Similarly, fair betting odds can be expressed as ”(1−p)/p to 1”, ”1/p for 1”, ”+100(1−p)/p”, ”−100p/(1−p)”, ”D−N to N”, ”D for N”, ”+100(D−N)/N”, or ”−100N/(D−N)”. In gambling, odds are often given as the ratio of the possible net profit to the possible net loss, and sometimes this is called fractional odds. Our basketball odds page brings together the games of the day, while results and standings go back several seasons. On the blocked odds page, you will be able to see matches or markets that online bookmakers are no longer offering odds for, which can signal a change in the market before other operators react to it.
In either case, having won, the bettor always receives the original best betting sites not on gamstop stake back too; so if the odds are 4/1 the bettor receives a total of £500 (£400 plus the original £100). Favoured by bookmakers in the United Kingdom and Ireland, and also common in horse racing, fractional odds quote the net profit that will be paid out to the bettor, should they win, relative to the stake. That value may be regarded as the relative probability the event will happen, expressed as a fraction (if it is less than 1), or a multiple (if it is equal to or greater than one) of the likelihood that the event will not happen. 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).
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. 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.
Major sportsbooks now operate nationwide, often adjusting their lines independently or using odds from other sources, not just Las Vegas. For decades, Vegas was seen as the gold standard for odds-setting, with casinos along the Strip acting as trendsetters for the broader betting market. Sharp action – bets placed by professional or experienced bettors – also triggers line movement.
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”. Multiplying these probabilities by 100% gives the percentage.
With the rise of online sportsbooks and the legalization of sports betting across many states, odds are no longer exclusive to Vegas. ”Vegas odds” traditionally referred to the betting lines set by Las Vegas sportsbooks, which were once the hub of sports betting in the U.S. When sharp bettors place heavy wagers, sportsbooks take this as a signal that these bettors have valuable information or insights.
A sports betting odds comparison that only shows the current price for the home win, draw and away win tells you less than one that also shows the opening odds and the payout of each bookie. The hockey odds page lists the next games with the best price for each team, next to recent results and standings. The fact that bookmakers have large teams of maths experts working out odds means that beating them at their own game can be very difficult.