When you bet on sports, there are usually three types of odds you will see and it all depends on where you live in the world. If you live in the US or anywhere in America, you should be familiar with the American odds where the standard odd consists of a plus (+) or a minus (-) sign with three-digit numbers like +100 or -220. However, outside of America, everyone is more familiar with decimal odds. These odds include decimals in their pricing, such as 2.10 or 1.70. It's different from the metric system as it's not hard to figure out. The last odds type is the fractional odds form that some books still use, but it's the least common.

Let's dive into the examples and explanations of each odd type below. To make things easier, let's use the Premier League favourites, Arsenal vs Liverpool, as an example, with Arsenal being the slight favourite.

American Odds

American Odds are the odd default forms at American sportsbooks. These odds are based on winning $100 for a single bet.

When you bet on a favourite team, the odds will have a minus sign (-) and represent the money you must risk to win $100. This means that if you bet on Arsenal at -140 against Liverpool, the Gunners are a slight favourite. And to win $100, you'll need to risk $140 on Arsenal. If they win, you'll receive $100 in profit with your initial $140 returned.

When you bet an underdog, the odds will have a plus sign (+) representing the money you can win for the $100 you've risked. In both cases, you'll get your original bet back, in addition to the bet you've won. The odds difference between the favourite and the underdog extends when the favourite football team's winning probability increases.

Decimal Odds

The majority of the world uses Decimal odds, partly because it's easier to convert into implied probabilities than American Odds. Decimal odds represent the amount you need to win for every $1 you bet. This number represents the total return instead of only showing the profit like American and fractional odds. In other words, your stake is already part of the decimal number and you don't need to add back your bet. This significantly eases the calculation process.

Let's say that Arsenal would be in 1.70 decimal odds as they are a favourite -140 in the American odds. This means that for every $1 you risk, you're winning 70 cents and your original $1 back.

On the other hand, Liverpool, a +120 underdog in American Odds, would be 2.2 when converted into decimal. This means that for every $1 you risk, you'll receive $1.20 profit and get your original $1 back.

Keep in mind that the odds also depend on the bookmakers. In this case, if the bookie determined that the chance of Arsenal (favourite) winning the match is higher than Liverpool. This means that the higher the total payout (the higher the decimal odds), the less probable it is for the team to win.

Fractional Odds

The fractional odds are most popular in the UK and Ireland. This type of odds is not very popular for sports betting except horse racing as it's difficult to understand the return conversions. Fractional odds are written with a slash "/" or a hyphen "- ". For example, "5/1" or "5-1" which is announced as "five to one."

To calculate your winning odds on this odds type, you must multiply your bet by the top number (numerator) and divide the result by the bottom number (denominator). This means that a $10 bet at 5/2 odds is calculated (10x5)/2, resulting in $25. Another example, a $10 bet at 3/5 odds is (10x3)/5, which is $6.

For example, let's say a sportsbook listed Arsenal at 10/11 odds and Liverpool at 9/4.

We can see that Arsenal is the favourite, while the odds for Liverpool are longer. This means that one only wins $10 against every $11 bet on Arsenal to be the winner. However, a win of $9 against every $4 is at stake for Liverpool to be the champion, which is less likely.

In the example above, if you bet $100 for Arsenal to win, you can make a $90.9 profit as $100 times 10/11 and you'll get your original $100 back, which is a total of $190.9 payout. However, if you bet on Liverpool to win with the same amount, you can score $225 in profit $100 times 9/4, and your initial $100 stake adds up to $325 of the total payout.

Conclusion

If you plan to enter the betting world, you need to understand the three betting odds instead of only one of them. Once you have mastered all these popular odds (American, decimal, and fractional), you can look deeper into this topic and find out why the house always comes out victorious.