How betting odds work: what they are and how to use them
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.
Opt in, deposit & bet £10+ on any Sports market at odds of 2.00 or greater within 7 days of registration. Free bet valid 7 days from issue, usable on any Sport/Market as a 3+ fold ACCA with total odds 3.00–21.00, each leg 1.50+. Bonus funds are separate to cash funds and subject to 10x wagering requirement (bonus funds). #AD 18+ New players only. Opt in, deposit and bet £10 on any football market (odds 1/1+) within 7 days of sign up.
Making a profit in gambling involves predicting the relationship of the true probabilities to the payout odds. The numerator and denominator of fractional odds are often integers, thus if the bookmaker’s payout was to be £1.25 profit for every £1 stake, this would be equivalent to £5 profit for every £4 staked, and the odds would therefore be expressed as 5/4. Before you rely on one, check how many bookmakers it covers, how quickly the prices are refreshed, whether it shows markets beyond the match result and whether it keeps the history of every price move.
Our experts rigorously test and only recommend sportsbooks that meet our high standards. 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.
Convenience is key, while reliability, functionality, live streaming, abundance of betting markets, and features are king. A “wholesale odds” index is an index of all the prices in a probabilistic market operating at 100% competitiveness and displayed without any profit margin factored for market participants. However, if the teams are evenly matched, both teams can have a negative line at the same time (e.g. −110 −110 or −105 −115), due to house take. The use of odds in gambling facilitates betting on events where the probabilities of different outcomes vary. 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 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. In gambling, the odds on display do not represent the true chances (as imagined by the bookmaker) that the event will or will not occur, but are the amount that the bookmaker will pay out on a winning bet, together with the required stake. In most cases, the favorite will have negative moneyline odds (less payoff for a safer bet) and the underdog will have positive moneyline odds (more payoff for a risky sports non gamstop betting sites uk bet).
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.
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.
