Sports Betting Odds: How They Work and How to Read Them

If you're new to sports betting, understanding how odds work is crucial. Whether you're betting in a casino, on sports, or any other event, knowing how to read and interpret different types of odds is key to placing smart bets.

The types of sports betting odds include:

• Fractional Odds (British): Common in the UK and Ireland.
• Decimal Odds (European): Popular in Europe, Canada, and Australia.
• Moneyline Odds (American): Widely used in the United States.

What Does it Mean When Odds Are Positive or Negative?

Moneyline odds (aka "American odds" or "U.S. odds") are popular in the United States.

• Favorites: Denoted with a minus (-) sign. The number shows how much you need to bet to win $100.
• Underdogs: Denoted with a plus (+) sign. The number shows how much you'll win if you bet $100.

For example, if a team has odds of -150, you'd need to bet $150 to win $100. If the odds are +200, a $100 bet would win you $200. In both cases, your original bet is returned along with your winnings. The larger the gap between the favorite and underdog odds, the higher the favorite's chances of winning.

Betting on the Moneyline: Example

Let's say a betting website (also known as an online sportsbook) priced an NFL game between the Pittsburgh Steelers and the Kansas City Chiefs with the following money line odds.

• Steelers: +585
• Chiefs: -760

The bookmaker has offered odds of +585 for the Steelers, which indicates that the bookmaker has placed a much lower probability (about 15%) that the Steelers will win the game. Therefore, if you risk $100 on the Steelers, you could win $585. If the Steelers pull off the upset, you get back your initial stake of $100 in addition to the $585 you won, for a total payout of $685.

If you decide to bet on the Chiefs—the team that, according to the bookmaker, has a higher probability of winning the game—you would need to bet $760 to win $100. If the Chiefs are victorious, you will win $100, for a total payout of $860 (initial stake of $760 + profit of $100).

In this matchup, there is a big difference between the two odds, indicating a much higher probability of the Chiefs winning the game. Often the odds are much closer.

How British/Fractional Odds Work

Fractional odds (aka "British odds," "U.K. odds," or "traditional odds") are popular among British and Irish bookies. They are typically written with a slash (/) or hyphen (-).

A fractional listing of 6/1 (six-to-one) odds would mean that you could win $6 for every $1 you wager as well as get the amount you wagered back. In other words, 6/1 is the ratio of the potential profit to the initial bet. Therefore, if you stake $10 at 6/1 and win, you'll get a total payout of $70 ($60 profit + $10 stake).

The total (potential) return on a stake can be stated as:

$\begin{aligned}&T_p=\bigg(S\bigg(\frac{N}{D}\bigg)\bigg)+S\\&\textbf{where:}\\&T_p=\text{The total payout}\\&S=\text{Stake}\\&N/D=\text{The numerator/denominator of the fractional odd }\bigg(\text{e.g., }\frac{28}{6}\bigg)\end{aligned}$​Tp​=(S(DN​))+Swhere:Tp​=The total payoutS=StakeN/D=The numerator/denominator of the fractional odd (e.g., 628​)​

Let's posit that the following are the odds on the three teams most likely to win the NBA Championship:

• Brooklyn Nets: 13/5
• Golden State Warriors: 9/2
• Milwaukee Bucks: 7/1

It can quickly be determined that the Brooklyn Nets are the favorites, while the perceived odds of Golden State or Milwaukee winning are longer. You would win $13 against every $5 you wager on Brooklyn to be the champions. Meanwhile, you'd win $9 against each $2 you put at stake for Golden State to win, and for Milwaukee, you'd win $7 against each $1 bet. 

In the above example, if you bet $100 on Brooklyn to win, you could make a $260 profit ($100 x (13/5)) and get back your initial stake of $100, resulting in a total payout of $360. However, if you wager $100 on Golden State to win, you could receive a profit of $450 ($100 x (9/2)) in addition to the $100 initial stake, leading to a total payout of $550.

The potential profit for a Milwaukee win would be even higher because you could make a profit of $700 ($100 x (7/1)). With your initial stake of $100 returned, it would result in a total payout of $800.

How European/Decimal Odds Work

Decimal odds (aka "European odds," "digital odds," or "continental odds") are popular in continental Europe, Australia, New Zealand, and Canada. These are a bit easier to work with and understand. The favorites and underdogs can be spotted instantaneously by looking at the numbers.

The decimal odds number represents the amount the bettor could take home for every $1 wagered—the total payout rather than just the profit. In other words, your stake is already included in the decimal number (no need to add back your stake), which makes the calculation easier.

The total (potential) return on a stake can be calculated as:

$\begin{aligned}&T_p=S\times D\\&\textbf{where:}\\&T_p=\text{The total (potential) return}\\&S=\text{Stake}\\&D=\text{The decimal odd}\end{aligned}$​Tp​=S×Dwhere:Tp​=The total (potential) returnS=StakeD=The decimal odd​

Let's look at an example involving who might have won the 2020 U.S. presidential election. Suppose the decimal odds were:

• Donald Trump: 4.00
• Joe Biden: 1.3

These numbers represent the amount you could win against each $1 you put at stake. So, if you bet $100 on Donald Trump to be reelected as president, you could receive a total payout of $400 ($100 x 4.00). This amount includes the initial stake of $100, resulting in a net profit of $300.

Similarly, you could receive a total payout of $130 ($100 x 1.3) if you successfully bet $100 on Joe Biden. Deducting $100 from this return gives you a $30 net profit.

Here we can see that the bookmaker correctly priced Biden as the favorite to win the election. The higher the total payout (i.e., the higher the decimal odds), the less probable it is that the candidate will win (in the bookmaker's opinion) and the riskier the bet is.

Different Types of Bets

Sports bettors have numerous options on the types of bets they can make. Here are a few of the most popular ones available:

• Over-under bets: Also known as a total bet, an over-under bet is a wager on whether a specific statistic for a game will be higher or lower than a quoted value from a sportsbook. The most common over-under bet is on the combined score of the two teams in a match. These are among the most popular sports-betting wager options.
• Parlay bets: When a bettor makes two or more bets and combines them into one wager, it's called a parlay bet (or an "accumulator" or "multi"). This type of bet is riskier than others because you have to win all of the small bets to win the parlay bet, and losing one means losing the whole parlay bet. They also have a bigger payout if all the wagers are won.
  
• Teaser bets: A type of parlay bet, a teaser bet allows the bettor to change the point spread for a game, which makes the bet easier to win, but also lowers the payout in the event of a win. The most common teaser bet is a two-team, six-point football teaser for which the bettor can adjust the point spread for two games.
• Prop bets: A prop bet is a wager on a game that isn't tied to its outcome. Prop bets might be on the accomplishments of individual players in a game, for example, or which player might hit a home run in a Major League Baseball game.
  

The Bottom Line

American, British, and European odds are three different ways of expressing the same thing and can be converted from one to another. By understanding all three and how they work, you'll increase your own odds of placing well-informed (if not always successful) bets.

If you or someone you know has a gambling disorder, please call the National Problem Gambling Helpline at 1-800-522-4700, or visit ncpgambling.org/chat to chat with a helpline specialist.