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

Navigating betting odds can be difficult for newer players – especially when you consider that there are multiple odds formats used throughout the wagering world. Whether it’s choosing the top online casinos in the US or the best online casinos in Canada, we help you play with confidence across slots, tables, live dealer games, and more. 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.

If you see +250, that team is the underdog; a $100 bet bookies 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.

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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.

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.

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). 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.

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. The value bets page compares the odds of each bookmaker with the average odds for the same outcome, highlighting the markets where one price stands out, with the probability included. OddsPortal has a number of betting tools that can bring your attention to interesting markets you may never have thought about betting on before, always with the best available price. The same price is 3/1 in fractional odds and +300 in American odds, which means a 100 bet wins 300 on top of the stake.

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. They give you a quick indication of how much you could expect to win if your bet wins.