Odds are an inevitable part of sports betting. Whenever you want to place a wager on a match or a race, you’ll see odds next to your selection. But, what do odds mean?

Sports Betting Odds Explained

If you are just getting into sports betting, you need to understand what types of odds are available to players and how to read/calculate betting odds.

Odds tell us two things:

  1. How much money you could win; and
  2. The probability of an event actually happening.

If you’re new to the world of sports betting, it’s completely understandable to be confused by all of the numbers displayed by betting sites.

That’s why we’re going to explain in details how do odds work in betting.

The first thing you must take into account is that odds come in three formats:

  • Decimal
  • Fractional
  • American (plus/minus odds) 

If you’re interested in learning how betting works and in mastering the odds before placing your first bet, make sure to read this comprehensive guide carefully.

What are odds and probability in betting?

football match odds example
Example from Bet365 bookmaker.

Simply put, odds are the chances of someone winning a game. In the example above, we have three outcomes — Everton winning, Arsenal winning, and a draw. You need to select one of the outcomes and place a wager

In this case, we’re looking at decimal odds, which are basically multipliers. Therefore, if you think Everton will win, and you’re ready to place a bet on it, you’ll receive a prize that’s 3.70 times your bet.

For instance, betting £10 will result in a £37 win, which includes a £27 profit.

However, odds can be more than an indicator of the probability of winning. They indicate the chances of any event happening. For instance, a bookmaker may set the odds of Salah scoring a goal against Everton at 3.50.

We use the term odds as a synonym for probability in everyday language, but that’s not really the case in sports betting. 

When a punter refers to odds, they mainly mean the number that’s always placed next to the betting options, such as 3.70, 3.60, or 1.95. These numbers imply probability as well, but their primary purpose is to determine your payout if you win a bet.

You can use odds to calculate the probability of an event happening (for money line, point spread or total points scored bets). We’ll discuss this in this article as well.

First of all, let’s see how decimal odds work. 

How to read decimal odds 

Decimal odds are represented by a decimal number, such as in the picture above. In this section, we’ll discuss these odds in more detail.

A higher number means that you’ll receive more money for a bet, but it also means the probability of winning the bet is lower.

Decimal odds are used in Europe (except for the UK and Ireland), Australia, New Zealand, Singapore, and Canada.

Here is a real-life example to demonstrate how decimal odds work.

At the moment of writing this article, there are several UEFA Champions League matches featured in many online sportsbooks.

decimal odds example

Manchester United (Man Utd) will welcome Young Boys to Old Trafford, and that’s expected to be an easy win for Man Utd players. 

Manchester United is one of the most popular football teams in history, even though this season isn’t their best overall. Still, they are one of the best teams in the English Premier League hosting a match against Young Boys, a long-time leader in the Swiss Super League. Regardless of how dominant Young Boys are in Switzerland, they are still an underdog compared to Manchester United, especially because they are playing away from home.

Therefore, the odds here are 1.40, which means that the probability of Man Utd winning this game is relatively high. For that reason, the payout will be quite low for anyone who makes this bet.

Simply put, if you bet £100, you’ll get £140 in return, which means that you will have made a £40 profit.

The odds of Young Boys winning this away game are 7.00, meaning that you’ll get £700 if you bet £100 (£600 profit). Essentially, it’s not likely to happen, but if it does, you’ll earn a nice sum. Still, you have to be realistic and bet on the underdog only when you’re informed enough to know that there’s a slight chance of that happening.

According to the image above, the draw is also unlikely to happen, with odds set at 5.00.

Here’s another example.

close decimal odds example

One of the most successful clubs from Portugal, FC Porto, is playing against one of Spain’s best, Atletico Madrid. However, in this example there is no clear favourite, judging by the odds provided by the bookmaker.

Even though Atletico Madrid isn’t the first team that comes to mind when someone mentions the Spanish La Liga (it’s usually Barcelona or Real Madrid), it’s still considered to be one of the best teams on the Iberian peninsula. However, so is FC Porto, as one of the two most popular clubs from Spain’s next-door neighbour.

As you can see, the odds for FC Porto winning are 2.75, whereas Atletico’s odds are 2.60. This is a tough call, and no matter which side you wager on, you’ll be making a somewhat risky bet, although your profit would be slightly higher if you bet on FC Porto. The highest odds are on the draw — 3.30, meaning you would receive £330 for a £100 bet.

How to read fractional odds 

In math, decimals can also be represented by fractions. This can be applied to odds as well. Instead of using decimal numbers, bookmakers in the UK and Ireland prefer fractional odds.

These are also referred to as British odds, UK odds, or traditional odds (used in the UK).

Fractional odds are pretty simple to read once you get the hang of them. 

The tricky bit is the fact that fractional odds represent your profit (not including the stake), whereas decimal odds represent the total payout.

fractional odds example

If you’re new to sports betting, this format can be somewhat confusing, but it’s pretty easy to understand once you get into it.

Real Madrid is one of the two most popular teams in Spain, next to Barcelona. Inter Milan is also one of the most successful teams in Italian Serie A. It’s always exciting to watch Spain and Italy’s best football teams lock horns. But who’s the favourite here?

When compared to decimal odds, the main difference is that fractional odds only represent the potential profit without counting the stake. If you think that Real Madrid will win and divide its fractional odds (11 divided by 10), you’ll get a total of 1.1. This means that if you deposit £100 and Real wins, you’ll make a profit of £110, but your entire prize payout will be £210. In this case, the decimal odds would be 2.1.

If you decide to wager on Inter Milan and divide 23 by 10, you’ll get 2.3, which means that your profit will be £230 if you bet £100. In the decimal system, this would be displayed as 3.3.

How plus and minus odds work

Plus and minus odds are often called moneyline odds, or American odds. This format uses a whole number with a + or - sign next to it. Moneyline is a bit different from fractions or decimals. Here’s a quick explanation.

Odds with a + sign tell you the profit you’ll receive if you bet £100. The odds with a - sign tell you how much money you’d have to bet to receive £100 profit. Confusing? Let’s examine a practical example.

minus and plus odds example

Benfica is another famous Portuguese club, on par with FC Porto. Dynamo Kyiv is the most successful football club in Ukraine. However, the Portuguese club is a clear favourite, and favourites usually have a minus sign next to them.

In this case, if you bet on Benfica, you’ll have to wager £334 if you want to win £100. If you decide to support Dynamo Kyiv and you wager £100, you’ll win a total of £900 as a profit. This is a much simpler way to think about odds, but it requires doing some math if you wager non-round numbers.

How American odds work

American odds are the same thing as minus and plus odds. It’s just another name for them, so if you stumble upon a format labeled as American, you’ll know what it is.

How to use odds to calculate probability and winnings

As stated above, odds have a two-fold role: to show potential winnings and to calculate probability.

We’ve explained above how to calculate winnings for every type of odds format. However, there’s one more thing we’d like to discuss: implied probability.

Simply put, this is just another way to display odds that will tell you what probability you have to pass your bet.

There are different formulas for calculating implied probability, depending on the odds format that you use.

implied probability odds example

For decimals, one is divided by the odds and multiplied by 100. Let’s use Ajax’s odds of 1.50 from the example above. Do note that probability doesn’t refer to the winning amount. If you want to calculate how much you’ll win, just refer to the odds. In this example, if you bet £100 on Ajax, you’ll receive £150 in return, meaning that your profit will be £50. On the other hand, betting on Sporting will result in a £600 return, or £500 profit.

(1 / 1.50) * 100 = 66.6%

It’s safe to say that Ajax is the favourite here. But what about Sporting?

(1 / 6) * 100 = 16.67%

Therefore, bookies suggest that Ajax has a 66.6% probability of winning. Using the same formula, we can calculate that Sporting has a much lower chance — 16.67%. The odds for a draw are 22.23%.

implied probability fractional odds example

In this case, if you bet £100 on Juventus, which is the favourite in this game, you’ll receive approximately £117 in return, or a £17 profit. It’s a pretty safe bet. If you want to take a risk, you’ll bet on Malmo FF, which is a heavy underdog, and receive a £1600 profit for a £100 bet.  

For fractional odds, you need to divide one by the fractional odds plus one and multiply by 100.

(1 / (1/6 + 1)) * 100 = 85.68%

Let’s do the same for Malmo FF, the famous Swedish football club.

(1 / (16/1 + 1) * 100 = 5.88%

This probability suggests that Malmo is a big underdog in the match, and betting on them would be a very brave wager that could also bring you a nice profit.

implied probability american odds example

In this case, betting on Bayern Munich will result in a £65 profit for a £100 wager. On the other hand, wagering on Barcelona comes with a £420 return, or £320 profit for a £100 bet. 

To convert positive odds into probability, divide a 100 by the given odds plus 100. Finally, you need to multiply the given result by 100. American odds for Barcelona winning the game are +320.

(100 / (320 + 100)) * 100 = 23.8%

Even though Barcelona is one of the most successful European clubs, they are facing German heavy artillery: Bayern Munich, one of the contenders for Europe’s best ever. According to the odds given, sportsbooks don’t think Barca has a big chance of winning. 

Things are a bit more complicated with negative odds. First, you must multiply the negative odds by -1, and then use that value in this formula: odds divided by the odds plus a 100 and multiplied by a 100.

The odds for Bayern Munich to win against Barcelona are -154. So, here’s the formula:

(154 / (154 + 100)) * 100 = 60.62%

In other words, bookies believe that Bayern Munich is much more likely to win the upcoming match.

If you’re into math, calculating probabilities isn’t much of a challenge. If you hate math, you’ll have to get used to the fact that it’s the essence of sports betting. 


To sum up, odds are a vital part of sports betting, and to participate, it’s essential that you can read them properly and determine probabilities based on them.

The first step toward winning bets and becoming a successful sports bettor is choosing your preferred odds format and knowing how to use it. So, make sure to select the format that seems most comfortable to you and open an account in an online sportsbook (look for the sign-up bonus, if any).

After that, find the option to change the odds format and set it to the one that you favour.

Once you make a couple of bets, calculating probabilities and payouts will become a piece of cake as you’ll train your mind to convert odds. After that, you’ll be able to explore various sports and sports betting markets, and apply complex betting strategies.