How Do Odds Work in Betting?

There are three different formats for odds

If you are planning to start betting—be it casino gambling, sports betting, or any other type—it’s important to understand the odds. Placing bets intelligently requires having a good grip on the main types of betting odds and the ability to read and interpret their various associated formats.

The three main types of betting odds are fractional (British) odds, decimal (European) odds, and money line (American) odds. These are simply alternate ways of presenting the same thing and hold no difference in terms of payouts. This means that the chances (or the percentage probability) of an event occurring can be converted and presented in any of the aforementioned types of odds.

Key Takeaways

  • The three main types of betting odds are fractional (British) odds, decimal (European) odds, and moneyline (American) odds.
  • These types are alternate ways of presenting the same thing and hold no difference in terms of payouts.
  • Fractional odds are the ratio of the amount (profit) won to the stake.
  • Decimal odds represent the amount one wins for every $1 wagered.
  • Moneyline odds, depending on the negative or positive sign, either indicate the amount one needs to wager to win $100 or the amount one would win for every $100 staked.

How 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 (-) and are used by some of the world’s largest bookmakers.

A fractional listing of 6/1 (six-to-one) odds would mean that you win $6 against every $1 you wager, in addition to receiving your dollar back (i.e., the amount you wagered). In other words, this is the ratio of the amount (profit) won to the initial bet, which means that you will receive your stake ($1) in addition to the profit ($6), resulting in a total payout of $7. Therefore, if you stake $10 at 6/1 and win, you get a total payout of $70 ($60 profit + $10 stake).

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

Total Payout = (Stake x (Numerator/Denominator)) + Stake Where: numerator/denominator is the fractional odd (e.g., 28/6)

Let’s posit that the following are the odds on the three teams most likely to win the 2022 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 odds on Golden State and 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, which is a bit less probable. 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 the initial stake of $100 returned, it would result in a total payout of $800.

How 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 one wins for every $1 wagered. For decimal odds, the number represents the total payout, rather than the profit. In other words, your stake is already included in the decimal number (no need to add back your stake), which makes its total payout calculation easier.

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

Total Payout = Stake x Decimal Odd Number

Let’s look at an example involving who might have won the 2020 U.S. presidential election.

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 the $30 net profit earned.

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 odd), the less probable (and riskier) it is for the listed candidate to win.

How Money Line Odds Work

Money line odds (aka “American” odds or “U.S.” odds) are popular in the United States. The odds for favorites are accompanied by a minus (-) sign and indicate the amount you need to stake to win $100. The odds for underdogs, on the other hand, are accompanied by a positive (+) sign and indicate the amount won for every $100 staked.

In both cases, winners get their initial wager back in addition to the amount won. The difference between the odds for the favorite and the underdog widens as the probability of winning for the favorite increases.

Let’s understand this with the help of an example:

Let’s say a betting website 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. You need to risk $100 on the Steelers to make a potential win of $585. If the Steelers can pull off the upset, you get back your initial stake of $100 in addition to the $585 won, giving you a total payout of $685.

If you decide to bet on the Chiefs—the team that, according to the bookmaker, has a higher implied probability of winning the game—you would need to bet $760 to win $100. If the Chiefs are victorious, you win $100 with 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.

In 2018 the Supreme Court gave U.S. states permission to legalize sports betting if they wish to do so. It is still fully illegal in 17 states, including California, Massachusetts, and Texas. In 4 other states, there is some form of pending legislation.

What Are Five-to-One Odds?

Five-to-one odds imply that every $1 wagered could win you $5 if the bet is successful. With fractional odds, the number on the left expresses how much you win, while the number on the right reveals how much you need to stake.


What Are +200 Odds?

When odds are expressed with a + or a – followed by a number, they are American money line odds: +200 signifies the amount a bettor could win if wagering $100. If the bet works out, the player would receive a total payout of $300 ($200 net profit + $100 initial stake).

Are Negative or Positive Odds Better?

Negative numbers are reserved for the favorite on the betting line and indicate how much you need to stake to win $100. Conversely, positive numbers are attached to the underdog and refer to the amount you could win if you bet $100.


If you are certain of a winner, you stand to make more money on positive odds. When you bet on the bookies’ favorite, you generally have a better chance of winning but also get a lower payout.

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

The Bottom Line

If you are planning to enter the betting world, it is important to be able to understand and interpret all types of odds well. You need to be familiar with the conversions between the different formats of odds, the conversion of odds into implied probabilities, and the differences between the true chances of an outcome, as well as the odds on display. Only then can you place a well-educated bet.

Article Sources

Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. Paddy Power. "How Do Odds Work?"

  2. SBO.net. "Explaining Decimal Odds."

  3. TheLines. "What Is A Moneyline Bet?"

  4. American Gaming Association. "Interactive Map: Sports Betting in the U.S."

  5. American Psychiatric Association. "What Is Gambling Disorder?"

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