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

Covers leads the way in delivering trusted sports betting insights and analysis for 30 years and counting. Tap into our sports betting community to get the most out of your next bet. Learn from and share your tips & picks with your fellow sports bettors. The odds or amounts the bookmaker will pay are determined by the total amount that has been bet on all of the possible events. Sports information services are often used by professional and semi-professional sports bettors to help achieve this goal. It was about 3.7% less for wins by the visitors, and 5.7% less for draws.

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). For example, “odds of a weekend are 2 to 5”, while “chances of a weekend are 2 in 7”.

A “moneyline” wager refers to odds on the straight-up outcome of a game with no consideration to a point spread. For example, 6/5 fractional odds (also described as “1.2” or “6 to 5”) are the same as 11/5 decimal odds (also described as 2.2 or “11 for 5). A variation of fractional odds is known as Hong Kong odds. However, not all fractional odds are traditionally read using the lowest common denominator (i.e. simplifying the fraction when possible). In either case, having won, the bettor always receives the original stake back too; so if the odds are 4/1 the bettor receives a total of £500 (£400 plus the original £100).

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. If you see +250, that team is the underdog; a $100 bet would return $250 if they win. Moneyline bets are the simplest form of sports betting, focusing solely on picking a winner. Some bets involve combining multiple outcomes for higher rewards, while others target specific in-game events or achievements. Once you’re familiar with the basic math, fractional odds become an easy way to see potential profits relative to the stake.

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. They give you a quick indication of how much you could expect to win if your bet wins. Min £10 qualifying bets stake not returned.

Moneyline, or American, odds are favoured by US bookmakers and punters, and are often expressed as positive and negative values (e.g. +250, -400). Bet £10+ on any sportsbook markets at odds of evens (2.00) or greater. “Double the odds” applies to fractional odds profits only, with extra winnings paid in cash on settlement.

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. You can check the opening odds of each bookmaker, follow the odds movement over time and compare it with the current odds, so you know how the market has reacted before you decide when to bet.

From local leagues to international tournaments, our website shows the top price for every outcome before you bet. OddsPortal is a free odds comparison site where you can compare betting odds from leading bookmakers on every match. Odds comparison, also known as line shopping, means checking the price of the same outcome at several bookmakers and taking the highest one. With results, standings, predictions and the best odds on the same site, you can check the top price before every bet. We also compare prices on boxing and MMA, where big fights are added as soon as bookmakers publish odds, on esports and on rugby union, rugby league, baseball, volleyball, Aussie rules and many more. Our tennis odds page compares the prices on every match of the day, next to past results and the odds they bookmakers non gamstop closed at.