How to Read Odds at Gambling Sites

Odds Explained

Betting odds indicate how likely the bookmaker considers your selection to be, and therefore is essentially a way of representing probability. Take fractional odds, the most common way to present odds in the UK, as an example. If you were to place a bet on the toss of a coin, the odds of it being heads would be 1/1, meaning there’s a 50% chance of it happening. As such, if you were to place £10 on that outcome, you would receive £20 back — your original stake plus a £10 profit. These odds are also referred to as ‘evens’. 

Of course, not all betting odds are quite as simple as a 50/50 coin toss, and are likely to change depending on a number of factors. Anything can happen in the lead up to a sporting fixture or event, such as an injury to a key player, that will change the probability of certain outcomes. 

Gambling sites will also price their betting markets against the number of bets that are placed in the run-up to an event. If the vast majority of bets are placed on a specific outcome, the odds are likely to diminish, resulting in more favourable — and often more accurate — odds being offered for the opposite result. More information, both on the event in question and where bettors are putting their money, gradually changes and improves the accuracy of betting odds.

Casino Odds vs Betting Odds

Although we said not all odds are as easy to calculate as the outcome of a coin toss, when it comes to online casino games sometimes it really is that simple. The chances of the roulette ball landing on a red or black pocket, for example, haven’t changed since the game was devised in 18th-century France, which means that those odds will always stay the same. Even in games such as blackjack and poker, probabilities can be calculated depending on how many cards are left in the deck. 

Fixed odds on casino games are also influenced by RTP (‘Return to Player’) rates and the house edge. The house edge is the percentage of money that the casino expects to earn back from the total amount that’s wagered on a particular game over time. In blackjack, for example, the house edge tends to be around 1%, which means that the house keeps around £1 for every £100 wagered. Conversely, this would make the RTP rate 99%. Of course, these figures have no real bearing over each individual hand, but these fixed odds ensure that the house always wins in the long run. 

Sports betting on the other hand, as we’ve already seen, is based on variable odds that will be constantly changing depending on a number of different contributing factors. 

How to Read Fractional Odds

Now that we’ve understood what odds are and how they’re calculated, it’s time to look at the different ways of presenting them. 

Fractional odds are the most commonly used in the UK, and are also perhaps the easiest to read. Fractional odds simply tell you how much you will win in relation to your stake, and this is also an indication of probability. We’ve already looked at an example of 1/1 odds, which means you will get paid back the same amount as your stake, and that the outcome is 50% likely. Odds of 4/1 means that a £10 bet would see you receive £50 back (your initial £10 stake and a £40 profit), and the same stake on a 1/4 bet (which equates to a probability of 80%) would see you receive £12.50. 

When the odds are a little more complicated — like say, 7/2 — the best way to understand them is by thinking that if the event in question was to happen nine times, your selection should win twice. 

And as for figuring out the payout, the left number is the profit you’ll win from a winning stake of the right number — so if you bet £2, you’d win £7 profit and walk away with £9 in total.

How to Read Decimal Odds

When it comes to reading decimal odds, all you need to do is multiply the decimal number by your stake in order to figure out your potential winnings. So, the higher the probability, the lower the decimal odds will be. Odds of 1/1 in decimal form, for example, would be 2.0. So if you were to bet £10, you would get a total of £20 back (£10 x 2.0). 

A less probable 4/1 bet, however, would be represented with odds of 5.0. Here, a winning bet of £10 would net you £50 in total — your £10 stake plus a £40 profit. 

How to Read American Odds

Though not very common at UK gambling sites, you may come across odds that are presented in the American fashion. Known as the moneyline, American odds are expressed as either a positive or a negative number. Let’s take a look at an example of an NBA game to help simplify things. The Heat are playing the Celtics, and the odds are:

• Miami Heat to win: +250
• Boston Celtics to win: -300

This makes the Celtics the firm favourites, and if you were to place a successful £10 bet on the Heat at +250, you would receive £35 back (including your initial £10 stake). The +250 odds essentially means that you will win £250 for every £100 you stake.

Negative odds are calculated slightly differently, however. Odds of -300 — which is the equivalent of 1/3 — mean that you will win £100 for every £300 you stake. Therefore, a winning £10 bet on the Celtics would get you £13.33.