Acing Tennis Betting Odds Formats: Fractional, Decimal & American

Understanding the different formats of tennis betting odds

Looking to understand the basics and advanced features of tennis betting odds formats? We have a solid guide here that covers every aspect of these different ways that tennis betting odds are represented and how you can easily interpret them.

While tennis betting is an exciting way to follow the sport and while it’s also a plausible career in the making for a few too, it’s quite imperative to understand its basics. Especially if you are new to the world of betting in general and tennis punting in specific.

One of the foundations on which the success of your tennis betting journey would be based on is the understanding of the various betting odds formats.

Introduction to Tennis Betting Odds

What are Tennis Betting Odds?

The very basic definition of tennis betting odds or any kind of betting odds in general is the prediction made by those offering those betting odds who will win.

Now understandably, this is a very rudimentary definition of what tennis odds mean but in essence that’s what it means.

Bookmakers offer odds to a tennis punter based on their understanding of which of the two players deems to have a better chance of winning the match. These odds will imply how much money will punters earn if their prediction comes right.

Odds on offer for the ‘favourite’ player will afford lesser returns than that for the ‘underdog’.

In essence, tennis betting odds are like guesses about who will win a game of tennis, and they help people decide how much they might win if they bet on a certain player.

The same concept can then be extended to not just the winner of the match but to all kinds of tennis betting markets. And there are multiple other such markets like the following:

  • Number of sets in the match
  • Number of games in the match
  • Who will win the first set?
  • Exact set-score of the match and so on.

The lower the probability of an outcome happening, the higher is the payout reflected in the betting odds.

For instance, a bookmaker could offer 1 unit of money back for every 2 units of money bet on Novak Djokovic in his match against Alexander Zverev. So if punters bet 10 bucks on Djokovic to beat Zverev and that’s what actually happens, they stand to gain five bucks (over and above their investment of 10 bucks).

Zverev, in the same match, could return the punters nine bucks on every five bucks bet.

What this also means is that Djokovic had gone into that match against Zverev as a favourite.

Importance of Understanding Odds in Tennis Betting

Now that you have some idea about tennis betting odds, let’s move to why it’s so vital to understand what odds mean in tennis betting.

Having an in-depth idea about betting odds in tennis is the cornerstone to your success as a tennis punter and this can be explained below. This is how understanding tennis betting odds helps a bettor.

  • Informed Decision-Making: Without knowing what odds mean, one is shooting in the dark while betting on tennis. Just one glance at the odds allows you to understand what outcome has a better probability of happening and then based on your own knowledge of the sport you can bet on or against it.
  • Identifying Value Bets: If you really understand your tennis, then understanding betting odds can also help you give an idea about value bets. Based on your knowledge of tennis, you would know that the probability of an event happening is bigger than the implied probability based on the odds on offer. This would allow you as a tennis punter to find opportunities where the potential return outweighs the perceived risk, leading to potentially profitable betting decisions.
  • Managing Risk: Betting odds offered by the bookmakers also help punters realise the probability of different results, which in turn allow them to adjust their betting strategies, stake sizes, and risk tolerance.
  • Maximizing Returns: One way to maximise one’s returns it to understand which bookmaker is offering what odds for a particular outcome. Other than identifying mispriced odds for a particular outcome, if a tennis punter understands odds well, he/she could use the discrepancies between different bookmakers to gain potentially higher profits.
  • Enhancing Strategy: Other than being an indicator of value, bettors can also use betting odds as a part of their strategy to develop a more structured and disciplined approach to their betting activities. Use odds along with other aspects of the sport like player form, head-to-head records, and playing conditions and it could help punters make solid betting decisions.

Now that you have a fair idea about what tennis betting odds are and what is their purpose, we move on to explaining the various formats in which these odds are denoted.

Types of Tennis Betting Odds

There are different ways in which odds can be represented. While the format for each of these are different, the returns of a pick from a particular betting market offered by a bookmaker will be the same at a given time irrespective of the type of odds.

The three main formats which are used to represent tennis betting odds include:

  • Fractional Odds
  • Decimal Odds
  • American Odds

Fractional Odds

As the name suggests, fractional odds are the type of odds which are represented as fractions (remember those fractions from way back in your school math class?). They are also called traditional odds or UK odds.

Fractional odds express the potential profit relative to the stake and are commonly used in the United Kingdom, Ireland, and other parts of Europe.

As mentioned earlier, these are presented as a fraction, typically in the format of ‘a/b’ and are read out as a to b where

  • ‘a’ represents the potential profit for the punter
  • ‘b’ represents the stake made by the punter

Let’s consider the Indian Wells Masters 2024 semifinal match between Carlos Alcaraz and Jannik Sinner in which the following winning odds were offered for each of the players:

  • Alcaraz: 11/10
  • Sinner: 10/13

In the example above, what it meant was that a bet of 10 units on an Alcaraz victory would earn a profit of 11 units if he won. Similarly, a bet of 13 units on a Sinner would earn the punter a profit of 10 units if he overcame Alcaraz.

In both these aforementioned cases, the bettor would earn that profit over and above the stake made (i.e. 10 units in the first example and 13 in the second).

In summary, fractional odds represent the ratio of potential profit to the stake and indicate how much a bettor stands to win relative to their wager.

They provide a clear and straightforward way to understand the potential returns from a bet in tennis betting and other forms of sports betting.

Converting Fractional Odds to Implied Probability

As mentioned earlier, odds are also a window into the implied probability of an event occurring and in order to calculate that from fractional odds, this is the formula one needs to use:

  • Implied Probability of an Event for Fractional Odds of a/b = b/(a+b).

So in the above example, the implied probability of Alcaraz beating Sinner in that match was 10/(10+11), i.e. 10/21 = 0.476 (which is then represented in percentage terms as 47.6%).

Similarly, the implied probability of Sinner winning that encounter was 13/23 = 0.565 (or 56.5%).

Decimal Odds

The second common tennis betting odds format is the decimal odds and use the decimal point system instead of a fractional one to represent the returns.

What’s also different from the fractional odds is that the decimal odds give you the total returns that you make on a stake of 1 unit, i.e. a total of the stake and the profit.

As mentioned earlier, decimal odds are represented by a decimal number which is greater than 1.00 because it represents the original stake of 1 unit and also adds profit on to it. The decimal number represents the total payout that a bettor would receive for a winning wager, including the original stake.

Let’s go back to the previous example of the match between Alcaraz and Sinner again.

If the same odds were represented in the decimal format, an Alcaraz win would be at 2.1 while Sinner would be pegged at 1.77.

What this implies is that a stake of 1 unit on an Alcaraz win would earn the punter a sum of 2.1 if he won while the bettor would take back 1.77 units home on a bet of 1 unit on a Sinner victory if the Italian achieved victory.

Converting Decimal Odds to Implied Probability

Again, we can find the implied probability of an event by using the decimal odds as well. The simple formula to do so when you have decimal odds provided is to divide 1 by the odds given.

So again, in the Alcaraz versus Sinner example above, the winning odds for the two players are at 2.1 and 1.77 respectively. What this means is that the implied probability of an Alcaraz win is at 1/2.1 and that of Sinner is at 1/1.77.

This works out to be same as before, i.e. 47.6% and 56.5% respectively.

American Odds

The third format of betting odds are called the American odds and as the name suggests, they are primarily used in tennis betting in the USA. These also go by the name of Moneyline odds.

What’s interesting to note about American betting odds is they are either positive or negative numbers, and just by looking at that, it’s easy for the punter to know who the favourite is.

A positive number in American odds denotes the amount of profit that a tennis bettor will earn if he/she bet $100 on an outcome. On the other hand, a negative number denotes the amount of money that a bettor needs to stake in order to make a profit of $100.

Let’s take an example here.

In the 2023 Miami Open, Elena Rybakina took on Petra Kvitova in the women’s singles final. Rybakina had gone into match at American odds of -300 while Kvitova was +230.

What this meant was that Rybakina was a whopping favourite with tennis punters needing to bet $300 to earn a profit of $100 if they put money on her victory. It also meant that betting on a Kvitova victory would earn bettors a profit of $230 for every $100 bet.

As it turned out, Kvitova went on to shock Rybakina 7-6 (14), 6-2 to earn those going against the favourite!

Converting American Odds to Implied Probability

Unlike the previous two formats, the calculation of the implied probability using American odds is slightly trickier because of the involvement of a positive and a negative number. The formulae for the two are slightly different.

Implied Probability for Positive American Odds:

Implied Probability = 100/(Positive American Odds + 100)

So, in the above case, the implied probability for a Kvitova victory was 100/(230+100) = 100/330 = 30.3%.

Implied Probability for Negative American Odds:

Implied Probability = Absolute Value of Negative American Odds / (Absolute Value of Negative American Odds + 100)

In the above example, the implied probability of a Rybakina win was |-300|/(|-300|+100) = 300/(300+100) = 300/400 = 75%.

Interpreting Tennis Betting Odds

Understanding Implied Probability

We have already made a mention of implied probability in the sub-sections under each of the three formats. In this section we look at what exactly does implied probability means and why is it so important.

Implied probability, as the name suggests is the probability that the odds offered by a bookmaker imply for a particular event to take place.

Based on one’s own perception of the probability of an event happening, a tennis bettor can use the implied probability offered by the bookmaker to understand if that betting market is overpriced, underpriced or rightly priced.

Let’s assume that an in-form (when is he not!) Rafael Nadal starts off a 1/3 favourite against Stefanos Tsitsipas in a Monte-Carlo Masters encounter and you, as a tennis bettor, reckon that the probability of Nadal winning this is 80%.

That’s way more than the implied probability according to the bookmaker which stands at 75%, which means that at 1/3, you have a good deal for this market with that bookmaker.

Identifying Favorites & Underdogs Based on Odds

Based on the odds on offer from the bookmaker, a tennis bettor can easily understand which of the players/teams starts off as a favourite. This same concept can be extended to any other tennis betting market as well.

In the cases of decimal and American odds, favourites and underdogs are easy to recognise.

Decimal Odds

The lower (or the lowest) of the numbers in case of decimal odds is the favourite.

For example, if, in a match between Rafael Nadal and Novak Djokovic, Nadal starts off at 1.75 and Djokovic is 2.2 to win it, the lower of those two numbers is 1.75 which makes Nadal the favourite.

American Odds

In case of American odds, the player or the market with the negative number is the favourite. And in case there are two results with a negative number, it’s the higher of the absolute values of those two which is a favourite.

So if Carlos Alcaraz starts off at -500 against Taylor Fritz who is +400, it’s Alcaraz who starts off a favourite. Fritz is a distant second in this case.

Let’s now take the example of an encounter between two evenly matched players, say Roger Federer taking on Novak Djokovic at Wimbledon. If Federer starts off at -120 while Djokovic is -110 to win this, it’s Federer who holds a narrow edge over his opponent according to the bookmaker.

Analyzing Odds Movements & Their Implications

It’s important to analyse the movement of the betting odds offered by bookmakers for the betting market you are interested in. It could give you an insight about something you might not be aware of otherwise or even help you formulate your strategy.

These movements of betting odds happen for a variety of reasons and could provide valuable clues to the punters.

It could be down to market sentiment with a change in market sentiment for reasons that you don’t know at that point.

When odds shorten (decrease), it indicates that more money is being bet on a particular outcome, suggesting increased confidence or consensus among bettors in favor of that outcome.

Conversely, when odds drift (increase), it suggests less support for the outcome, potentially due to new information, changing conditions, or shifts in sentiment.

You can understand this concept in greater detail by reading our exhaustive guide on the implication of odds movements here.

Comparing Odds Across Different Bookmakers

One of the more common but underrated strategies in tennis betting is the need to compare the odds for the same market between different bookmakers.

The reasons behind the need to do this is multi-fold, and we will cover all of it in greater detail in another piece. However, one of the biggest reasons for this is to get the best possible odds for a particular bet.

If you were backing Dominic Thiem to beat Roger Federer in their 2019 ATP Finals encounter, you would have got odds of $3.55 with Betsson and $3.88 with 1xBet for the same result.

Let’s assume you are a Betsson customer and put your money on a Thiem win with them. Thiem had gone on to defeat Federer in that encounter and the good news for you would be your bet would have come out a winner too.

The bad news is you would have left a substantial amount of money on the table by not signing up with 1xBet who were offering a whopping $0.33 more for the same result.

This is why it’s not just important to compare odd between different bookmakers it’s also vital to sign up with as many of them as there are legally available in your region.

Tennis Betting Odds FAQ

What do tennis betting odds represent?

Tennis betting odds represent the returns offered by a bookmaker on an investment made on an event by a punter. They, in turn, also recognise the implied probability of the event happening.

How do I read and interpret fractional odds in tennis betting?

Fractional odds are mentioned in a fraction form, i.e. a/b, with the top number (a) representing the profit made if a bet of the bottom number (b) is made on an event.

How do decimal odds work in tennis betting, and how are they different from fractional odds?

Decimal odds give the total returns on a bet of 1 unit (investment plus profit) made by a tennis punter instead of the profits that are shown using fractional odds.

Can you explain positive and negative American odds in tennis betting?

Positive American odds represent the amount made by a punter in case of a $100 bet and negative American odds is the amount one needs to bet to make a return of $100 on a bet.

How do I calculate the implied probability from tennis betting odds?

All three formats of tennis betting odds have a different calculation associated with them to calculate implied probability. Here’s how to go about them:

  • Implied Probability of an Event for Fractional Odds of a/b = b/(a+b)
  • Implied Probability of an Event for Decimal Odds of a = 1/a
  • Implied Probability for Positive American Odds = 100/(Positive American Odds + 100)
  • Implied Probability for Negative American Odds: Absolute Value of Negative American Odds / (Absolute Value of Negative American Odds + 100)

What factors influence tennis betting odds and the changes to it before a match?

Quite a few factors like Player Form and Performance, Head-to-Head Record, Injury and Fitness Concerns, Surface and Playing Conditions, Tournament Importance and Prestige, Public Perception and Betting Trends, Expert Analysis and Insider Information, Market Movements and Bookmaker Adjustments affect the betting odds in tennis.

Where can I find the best tennis betting odds online?

Almost all sportsbooks or bookmakers offer tennis betting odds. Make an account with a bookmaker of your choice or log in to your bookmaker and search for the list of sports offered – tennis will be one of them. Click on it and all the latest odds for almost every professional tennis match will be on show.

How do I compare odds across different bookmakers to find the best value?

The best way to compare odds across different bookmakers is to make accounts with as many bookmakers as you can. Once you have done that, use websites like OddsChecker.com, OddsPortal.com and OddsPedia.com to find the best value.

How important is understanding odds in developing a successful tennis betting strategy?

Without understanding what tennis odds represent, it’s almost impossible to develop a successful tennis betting strategy.

Are there any tools or resources available to help me analyze tennis betting odds more effectively?

There are multiple such tools to help you analyse tennis betting odds including Sports Betting Platforms, Odds Comparison Websites, Data Analysis Websites, Betting Communities and Forums, Expert Analysis and Tipsters, Betting Software and Tools, Bookmaker Promotions and Offers, Educational Resources like books, articles, tutorials, and online courses dedicated to tennis betting like a site like UltimateTennisGuide.com

What are the risks of focussing solely on odds when making tennis betting decisions?

There are multiple risks associated with focussing only on odds which include a limitation of your perspective, following short of finding value bets, losing perspective on subjectivity, falling prey to the market movements and lack of long-term strategy.

Can I bet on specific outcomes within a tennis match, such as game score or set winner?

Yes you can bet on not just tournament or match winners but also set score, game scores and as things stand right now, winner of the next point in live tennis betting with odds offered for each of them.

Final Words on Understanding Tennis Betting Odds

Understanding the different formats of tennis betting odds, the differences between them and their implied probability are all aspects of punting on tennis that a beginner must look to learn before kick-starting their tennis betting journey.

It’s that vital.

The aforementioned passages speak in-depth about these odds along with examples, making this a one-stop guide for everything related to tennis betting odds.