Sports betting is a popular pastime, enjoyed all over the world. Some like to bet casually, while some take it more seriously. Whatever your outlook or approach though, it is generally worthwhile to have at least a basic understanding of the odds.

What Are Odds?

Odds are basically a mathematical way of showing the chance of something. In sports betting:

  • They can give you a general idea of how likely it is that a bet will win, or lose.
  • They allow you to calculate how much a winning bet will pay out.

Generally, each sportsbook provides its own odds for its customers to use. There are three common types of odds used in sports betting around the world.

Decimal Odds

Decimal odds are a popular method used most commonly outside of the US. The following is an example:

Pittsburgh Steelers         2.6

Los Angeles Rams            1.4

Basically, the lower the number, the greater the chance there is of winning, or vice versa. So, in this example, the Rams are expected to win, while the Steelers are the underdogs.

To calculate the exact percentage, you can use the following formula:

1 ÷ (decimal odds) x 100 = percentage in chance of winning


Pittsburgh Steelers         1 ÷ 2.6 x 100 = 38.46 percent

Los Angeles Rams            1 ÷ 1.4 x 100 = 71.43 percent

Note that the resulting percentages equal more than 100 percent when added together. The extra percentage is to ensure the sportsbook receives a small cut from each winning bet, similar to the casino “house edge”.

To calculate the payout:

(decimal odds) x (bet) = payout


Pittsburgh Steelers         2.6 x $100 = $260

Los Angeles Rams            1.4 x $100 = $140

American Odds

The most common method around North America, American odds use plus and minus indicators to show the underdogs and favorites. For example:

Pittsburgh Steelers         +160

Los Angeles Rams            -240

The + symbol indicates the amount you will win in addition to a $100 bet. Therefore:

Pittsburgh Steelers         160 + $100 = $260

The – symbol indicates how much one has to pay to win $100. Therefore:

Los Angeles Rams            240 – $100 = $140

As you can see the resulting payouts are the same as the decimal system.

Fractional Odds

Fractional odds are the less common method of the three, though are still offered by some sportsbooks. The following is an example:

Pittsburgh Steelers         16/10

Los Angeles Rams            4/10

Betting on the Steelers will pay out $16 for every $10 wagered, and betting on the Rams will pay $4 for every $10. Dividing the first digits with the bet, and adding 1, you will give the decimal odds. Eg:

Pittsburgh Steelers         16 ÷ 10 + 1 = 2.6

Los Angeles Rams            4 ÷ 10 + 1 = 1.4

Gaining A Winning Edge

Understanding odds won’t guarantee wins. However, combining them with good info and knowledge of a game will give you a far greater chance for success. Furthermore, these days sites like Dunkel Index make things even easier for bettors by offering round-the-clock odds, ratings, and best picks for all major sports, events, and teams.