Odds Key and Sports Betting Odds Explained

What They Are And How They Are Calculated

In online sports betting, odds are the probability of an outcome. They represent the chance you stand to win and your total payout or potential profit. Understanding how odds work is a basic knowledge you need to succeed as a punter. In this article, our experts at BTA present a detailed explanation of betting odds and keys to help you make informed betting decisions. Read on to learn everything you need to know about sports odds.

As a punter, we are sure that YOU have come across the word “Odds” on several occasions. While almost every punter basically knows what odds mean, not everyone has in-depth knowledge of how they work, and how to calculate them. Odds are the basics of sports betting and it is essential that every punter is well-versed in the concept of Odds. By learning how to interpret, calculate, and make informed decisions on odds, you can evaluate the chances of your winning and determine what would be your potential payouts at any sportsbook.

We understand that knowing the full concept of betting odds may be challenging for some punters initially, but it is pretty straightforward once you get the hang of it. This is why in this comprehensive guide, we explain everything you need to know on betting odds. This helps us ensure that you are empowered with adequate knowledge of odds, which will help you make smarter choices while betting online. 

So, henceforth, don't let the complexity of odds deter you from maximising your gambling experience. We are here to make it a much simpler process, so, let's help you enhance your chances of WINNING at any bookmaker by educating you through this guide. Let's go on!

What Do Sports Betting Odds Mean?

Simply put, betting odds represent or show the likelihood of a sports event happening and are used in the gambling industry to determine the potential payout a punter would receive on a WINNING bet. That is, the odds show you exactly how much you can win. For example, if the odds are 2.20 and you bet $10, you can win ($10 × 2.20) which equals $22.00. Sounds cool, doesn't it! 

We can also say that the betting odds are the probability of winning being expressed as a number. So, the higher the odds, the more the profit on your payout increases, however, the probability of winning the bet decreases.

From the above explanation, we can see that odds can help you determine how much money you can win from a successful bet and provide you valuable insights into the perceived chance of winning the bet. One interesting fact about betting odds you may not know is that odds are beneficial to both punters and bookmakers. We can hear you say, But How? Don't worry, we'll tell you what we mean!

One of the advantages of odds to you as a punter is that it allows you to determine the likelihood of an event occurring and helps you to make informed decisions in the face of any bookmaker.

On the other hand, odds are also used by bookmakers to ensure that they make a profit regardless of the outcome of the event (whether you win or not) and one of the approaches with which they make this happen is via odds fluctuations and margins.

Betting odds can fluctuate based on the volume of bets placed, news events, and changes in circumstances related to the event being wagered on. They can also fluctuate based on the betting patterns of gamblers and new information that may influence the outcome of an event. 

In a similar but slightly different vein, the margin is a difference between the odds the bookmaker offers and the actual probability of that event happening. We will go into this explanation deeply later on this page. So, stay tuned. 

Most importantly, you need to understand that odds are a key factor when bookies and punters make decisions. Before we proceed, it is essential to note that the focus here is to help you understand betting odds. We refer you to our dedicated betting strategies, betting tips and predictions, and soccervista pages for other related information you need to win at betting sites

Types of Betting Odds 

To refresh what you have read, odds show the probability of an event happening. Now you know what odds mean, let's now delve more into advanced details about odds. In this section, we will take a look at the types of odds that we have. Typically, there are two types of odds, odds on and odds against. 

Odds on 

Have you ever been in a situation where you pick a game to bet on and after placing your stake, you realise that the payout is not up to the amount you wagered? This is called an odds on situation. In this kind of situation, the potential payout is lower than the amount wagered. 

In simple terms, odds-on shows you that the bookmaker believes that the outcome of a match or an event is more likely to occur than not. For example, if the odds of Real Madrid winning over Valencia in a Spanish La Liga match is 1/4, this means that for every $400 you wagered, you will only record a profit of $100.

Odds Against 

The odds against is the direct opposite of the odds-on situation. Through their names, you probably would have clocked this. Odds against refers to a situation where the potential payout of your Winning is higher than the amount of money you wagered. In other words, odds against means that a bookmaker thinks the outcome of an event is less likely to happen. 

For example, a few weeks ago, I staked on Arsenal qualifying for the 2024 UEFA Champions League quarter final over Porto despite losing the first leg to a late goal in Portugal. The odds were 4/1 at the bookmaker and my bet won. I made $400 on my $100 stake. This is an odds against situation, the odds were against Arsenal to qualify, and I bet for the North London team to qualify. I hope you take advantage of sweet betting options such as this in the future!!!!

These two types of odds are used in sports betting to indicate the likelihood of a certain outcome and the potential payout.

Sportsbooks Odds Format

Sometimes you may be surprised if you land at a sportsbook where the odds are presented in a different format from the famous decimal ones. Don't worry, you're not unsafe or being scammed, it's definitely normal. There are several types of odds used in the sports betting world, but the three most common types are the fractional odds, the decimal odds, and American odds also known as money line. In addition (although not common), betting odds can also come in the format of percentages, which is also known as implied probability.

We are now getting to crucial stages when it comes to betting odds. Understanding the various formats and how each works is crucial when making betting decisions. We NEED YOU to pay maximum attention here, as it has the potential to be the difference between making profits or losing money. By familiarising yourself with different odds formats, you can become a more informed bettor and make smarter betting choices. 

Decimal Odds 

You've probably come across odds presented in something like 1.01, 1.4, 2.11, 3.0 right? Decimal Odds are a popular method of displaying betting odds in many countries worldwide, probably the most popular. As their names imply, these odds are simply shown as a single decimal number, like the ones stated above.


How Do Decimal Odds Work?

Let's take an example. In a fiercely competitive Premier League season, table toppers Chelsea are scheduled to play against second place Liverpool at Stamford Bridge. If the bookmaker sets the odds at 1.8 for Chelsea to win and 2.2 for Liverpool to win, it means that if you bet $100 on Chelsea and they win, you will get back $180. In the same vein, if you bet $100 on Liverpool FC to claim the victory and they do, you get back $220. 

In another example, if another bookmaker sets odds of 3.00 on Manchester United to beat local rivals, Manchester City, this means that for every $1000 you wager on the Red Devils, you will win $3000 if United defeats Chelsea. 

Decimal odds have a distinct advantage; they are very simple to understand and require very little or no calculations at ball. They are also more precise and user-friendly compared to other types of odds.

Some of the biggest bookmakers in the world use decimal odds. The likes of 1xBet, Betking, Bet365, Unibet, Paripesa, and Betway are examples of bookmakers that use decimal odds. The aforementioned bookmakers also have provisions for other odds formats, however, the decimal odd is their default. 

Fractional Odds

Fractional odds are quite popular but are typically used in the United Kingdom. As the name implies, fractional odds are represented as fractions. A typical example of a fractional odd is 2/1. This odd means that for every $100 you bet, you will win $200 if the event you selected in your bet occurs.


How Do Fractional Odds Work?

Let's take a typical example of 1/2 to further aid understanding. In fractional odds, the number (1) from the example above indicates the potential payout, while the second number (2) indicates the original wager amount. For instance, if you place a bet of $100 on Team A with 5/1 odds and your ticket wins, you will earn $500 in total (5 x 100). That means $400 in profits in addition to your initial $100 stake.

Most bookmakers offer an option to switch to decimal or fractional odds. The likes of William Hill and Betway are examples of bookmakers that use fractional odds.

Money Lines (American Type of Odds)

By now we are sure that hearing “American Odds” have got you thinking “is it for America?” or “Is it used in America?” Well, you are RIGHT! As the name implies, American odds are used mostly in the United States. This format of odds are represented with positive or negative signs in front of the numbers. 


How Do American Odds Work?

In money lines or American odds, a positive number represents the underdog team (that is the least likely team to win), while a negative number represents the favourite team (that is the most likely team to win). The American odds have been designed to use a base value of $100. To calculate, have it at the back of your mind that YOU will always risk money to win $100 if you bet on favourites. On the other hand, you RISK $100 to win an amount if you bet on the underdogs. 

So, if you stake on a (-135) favourite, it means that you have to risk $135 to win a profit of $100. However if you stake on a (+350) underdog team, it means win a profit of $350 if you stake $100. 

So, let's say a football team has odds of +150, that means a $100 bet would result in a $150 payout. If a bookmaker sets the same team to have odds of -120, then, you need to place a $120 bet to win $100. Mostly, American focused bookmakers use the moneyline odds format. However, it can be found at many bookmakers nowadays. The likes of William Hill and Melbet are examples of bookmakers that use American odds.

Percentage Odds (Implied Probability)

You will probably clock that percentage odds are expressed in percentages. These odds are a method of expressing the probability of an event happening. 


How Implied Probability Odds Work?

In implied probability odds, bookmakers assign percentages to these odds, like 25% or 75%. The higher the percentage, the greater the chance of the event taking place. For example, if Manchester United are deemed to have a 75% probability of winning a premier league match against Chelsea, their odds would be 1.33 (100/75). Bookmakers like William Hill and Bet365 use the implied probability odds.

Having explained the odds format, we have to make you aware that in sports betting ODDS are different from PROBABILITY. Their similarity is that both are used in gambling to indicate the chances of an event occurring. However, a key difference is that probability is typically shown as a percentage, while odds can be displayed in decimal, fraction, or moneyline formats. 

You might also be interested in:

Factors That Determine Betting Odds

At the beginning of my journey into online betting, I often wondered how it is that the odds for a match may change after sometime. Initially, I thought it was some malfunction or probably the bookmaker trying to play a fast one! However, as time flew by, I got to understand perfectly the reasons why it happened. Are you also in this shoe? Odds play a central role in sports betting, and we understand that it is only natural for you to seek more information about them. So, don't worry, we'll explain more about it here. 

Some factors that determine betting odds include: 

Form and Performance of the Team/Key Player 

Football is always about 60% performance. While it may be different in some cases, the general rule is that you or your team needs to PERFORM to WIN. So, the recent form and performance of a team or its major player plays a significant role in determining their betting odds. For example, in the 2022/2023 season, Norwegian hitman Erling Braut Haaland was the spearhead as Manchester City stormed to a historic treble. 

So if before a game, Haaland was announced as injured or unable to play for some reasons, bookmakers would no doubt increase the odds of Manchester City winning the game as the probability is reduced due to losing their star striker. The same applies to the whole team, as a team in form is more likely to win than one in a bad form. An example is Arsenal who have been winning consistently this season compared to Chelsea who have been struggling.

Injuries and Suspensions

The absence of key players due to injuries or suspensions can have a big impact on a team's chances of winning a match. Would you rather bet on a Liverpool team with Egyptian talisman Mohammed Salah in the team to win? Or would you prefer to bet on a Liverpool team with him to win? We think you'd go for option A. So, as a result, the odds for that team may be adjusted to reflect the recent change in the squad.

Statistical Record

There are tons of statistics that enable bookmakers to adjust odds appropriately. An example is the head-to-head record. The head-to-head record between two teams can also influence their betting odds. If one team has a history of dominating the other, they are likely to have lower odds of winning. 

For example, Manchester City and Newcastle United have played 48 matches so far. City won 33 direct matches, Newcastle United won only 9 matches, and 6 matches ended in a draw. In this record, we can deduce that City is likely to beat Newcastle if they are to play tomorrow, and automatically the odds for a City win will be lower. 

Venue and home advantage

The venue of a match can also affect the betting odds. Home clubs are always given an advantage due to the support of their fans and familiarity with the surroundings, resulting in slightly or significantly lower odds for the away team.

Public Opinion

Bookmakers study people's betting patterns a lot. That is why they have a huge number of analysts working for them. They study people's opinions, how they place their bets and which team they wager on the most. This activity can also affect the bookmaker to change the odds. If a large number of bettors are placing bets on a particular team, the odds for that team may decrease as the bookmaker tries to balance out their liabilities.

Weather conditions

The atmospheric conditions are one of the major factors that can impact the outcome of a sporting event. Weather conditions are natural and can not be influenced by the players, teams or sports association. They affect a large number of sports, especially outdoor ones like football, tennis and more. For example, heavy rain can favour one team over another and may lead to changes in betting odds.

Betting Odds Calculator - How Odds Keys are Calculated 

By now, you can see how important adequate understanding of betting odds is crucial for bettors to make informed decisions in the sports betting industry. In fact, it could be the difference between a beautiful or terrible betting experience. As a punter, YOU can use odds to determine the amount of money to be won or lost in a bet. 

We mentioned earlier that Betting odds are a crucial component in all forms of betting, serving as an assessment of the probability of an event taking place. We also went further to tell you the types and forms of betting odds. Now, you need to know that each odd type has its own unique way of calculating the probability of an event occurring.

How Decimal Odds Are Calculated 

Decimal odds are shown in decimal form, and are quite popular in many regions around the globe including Europe and Africa. Decimal odds are very easy to understand and pretty straightforward. 

They are calculated by dividing 100 by the implied probability of an event happening. So, the formula to convert implied probability to decimal odds is:

[Decimal Odds = 100 / Implied Probability]

For example, if the implied probability of an event happening is 50%, the decimal odds would be 100 / 50 = 2.0. This means that if you place a bet of €500, your potential winnings would be €1000. 

Likewise, if the implied probability of an event occurring is 20%, the decimal odds would be: Decimal Odds = 100 / 20 = 5. This means that if you wager a bet worth £100, your potential winnings would be £500.

How Fractional Odds Are Calculated

Fractional odds are calculated by dividing the potential earnings by the amount you wager. For example, if the odds are 5/1, this means that for every 1 unit of money staked, your potential earnings is 5 units. 

To calculate the probability implied by fractional odds, you can use the formula: Probability = Denominator / (Denominator + Numerator). 

For example, for odds of 5/1, the implied probability would be: Probability = 1 / (1 + 5) = 1/6 = 16.67%. Likewise, odds of 2/1 would have an implied probability of: Probability = 1 / (1 + 2) = 1/3 = 33.33%

How American Odds Are Calculated 

American Odds or money line represents the amount of money you are to place on an event to win $100 profit if your bet is successful. American Odds come either in positive or negative numbers.  

To calculate American Odds, the following formulas can be used:

Positive odds: (Profit / Initial Bet) ×100 = American odds.

For example, if you win $200 on a $100 bet, the American odds would be: (200 / 100) ×100 = +200.

Negative odds: (Initial Bet / Profit) ×100 = American odds. 

For example, if you must bet $150 to win $100 profit, the American odds would be: (150 / 100) ×100 = -150.

How Implied Probability Odds Are Calculated 

At Betting Tips Africa, we believe that any topic worth teaching at all is worth teaching well. So, we have described how to calculate the implied probability of various odds formats, however, we won't stop there. We want you to have a full understanding of odds calculation, so we will now discuss how to convert the different formats of odds into implied probabilities.

Implied probability odds are calculated by converting traditional odds (such as decimal, fractional, or American) into a percentage that represents the likelihood or probability of a particular outcome occurring. 

(i) To calculate implied probability from decimal odds, you would use the formula: Implied Probability = 1 / Decimal Odds. Let's assume the decimal odds for Bayern Munich defeating Borussia Dortmund is 2.00, the implied probability would be: 1 / 2.00 = 0.50 or 50%. This means Bayern Munich has a 50% chance of beating BVB. 

(ii) To convert fractional odds to implied probability, you would use the formula: Implied Probability = 1 / (Fractional Odds + 1).

(iii) On the other hand, for American odds, the formula varies:

For positive American odds (e.g. +150), the formula is; Implied Probability = 100 / (positive American Odds + 100). For negative American odds (e.g. -150), the formula is; Implied Probability = (Negative American Odds) / (Negative American Odds + 100).

NOTE: Understanding the principles behind odds calculation, meaning and conversion can assist you in determining whether a bet is worth staking. If you are able to determine which odds are worth it, then the odds of you winning WILL improve significantly.

Why Bookmakers Change Betting Odds Explained

There are several reasons why betting odds change before or even during a game. This could be due to early lead in live betting, market forces, tactical shifts, red cards or injuries. Here, we thoroughly check out these factors, so you can be prepared ahead of any unforeseen circumstance. 

Early Lead in Live Betting

In live betting, let's assume Team A takes an early lead early into the match, the odds of Team A winning will most likely decrease as they are marked to have a higher chance of winning the encounter. However, the odds for Team B that conceded the early goal may increase as they are seen as less likely to make a comeback. Let's say Tottenham Hotspur concedes a fifth minute goal away at AC Milan's San Siro. Automatically, the bookmaker sees AC Milan as most likely to win and would adjust the odds accordingly. [i.e Tottenham Hotspur's odds go up, while Milan's odds lower a bit].


Injuries are not pleasant and no team wishes them upon their players. However, it is a part of the game and there is almost nothing that can be done to stop them. Injuries cause players to miss games, which simultaneously means a change in odds. 

Injuries can happen just before the game or during the course of the game. Whichever time it occurs, the bookmakers will adjust the odds to balance it out. You would feel more confident betting on Paris St Germain to win a game if Kylian Mbappe is on the pitch rather than when he's not, isn't it?


Suspensions can happen for reasons ranging from violent conduct, dissent to accumulation of cards. If a key player is suspended before a match, it will impact the betting odds. For instance, if Mohammed Salah, Liverpool’s current leading goal scorer in the 2023/24 season is suspended for a crucial match, the odds of the Reds winning may decrease as they would be missing a key player who almost drags the attack all by himself with worldly abilities. 

Market Movements

Betting Odds are also affected by market movements and modifications in the betting market. Bookmakers constantly adjust the odds to ensure that they are offering competitive prices and to account for any changes in the market.


Red cards and yellow cards are used to caution players who played dangerously or showed unacceptable behaviour. Obviously, if a team has one of their players sent off or many of their key tacklers yellow-carded, it would have a significant negative impact on the team. In such a case, bookmakers would adjust the odds on offer to reflect the other team's likelihood to get a result.


As we have hammered on since the beginning of this page, we would like to remind you that whether you are a newbie, professional or veteran, understanding how betting odds work is highly important. 

Odds are like the beginning and end of sports betting, so you have to get the hang of it. Odds tell the likelihood of a certain event happening and determine how fat your payout is going to be. YOU want the FAT one right? Then you have to understand the different types of betting odds, including the odds on display.

We are committed to providing you crucial information on how to make profit from sports betting, and which better way than to know your way around the odds? All the types of odds, their formats and real life examples are already discussed here. Ensure you understand fully every information on this page, and we can guarantee that you will become a better BETTOR in every aspect.  

Our Predictions:

Bundesliga PredictionPremier League Prediction
Ligue 1 PredictionSerie A Prediction
Africa Cup of Nation PredictionChampions League Prediction
NBA PredictionFriendly Matches Prediction
CAF Champions League PredictionEuropa League Prediction
Championship PredictionBundesliga 2 Prediction
DFB Cup PredictionLa Liga Prediction
World Cup Prediction 

Overview Predictions at bettingtipsafrica.com