Odds to Percentage and Probability: How to Convert Betting Odds

Posted on September 1, 2022 - Last Updated on September 7, 2022

With esports betting becoming more and more popular, it’s good to know how to convert the different types of esports odds. These betting odds come in several forms. In this article, we will identify the different types of odds you’ll likely find, including decimal, fractional, and American odds. We will take you through the basics of each of them, demonstrating their mechanics with useful examples so that you may fully understand what the various types of odds mean. The objective of our article is to guide you on how to convert odds to percentages and probabilities – this can be helpful when you want to understand the logic behind the odds you are seeing.

How to Convert Odds to Percentages and Probability

The three main types of esports betting odds are the following are decimal odds, fractional odds and American odds. In this section, we’ll describe each type briefly, then move on to explain how to convert these odds to percentages and probability.

1. Decimal Odds

Decimal odds are called decimal because they come in decimal form.

Examples include 1.80, 2.40, 4.00 and so on.

The meaning of these odds is very simple: your total returns are whatever the odds show you multiplied by the amount you wagered.

So if you bet $5 that team A will win the match and team A’s odds of winning are 1.80, you get a return of 5 * 1.80 = $9. If you wager $20 on a team whose odds are 4.00, the amount you get in case of a win will be 20 * 4.00 = $80.

Convert Decimal Odds To Percentage
Decimal Odds

Two things you’ll want to know here are how to convert odds to percentages and how to convert betting odds to probability.

How to Convert Decimal Odds to Percentages

Another way of understanding decimal odds is using percentages.

So instead of 1.80, think of this as 180%. Instead of 2.40, think 240%. And 4.00 would actually mean 400%.

Of course, these percentages include the amount you’ve wagered. So it’s not 180% profit but 180% returns. The profit is actually just 80%. In the second case, the profit is 140%. In the third it’s 300%.

So you always have to decrease your initial amount or 100% in order to find what you’re actually making.

How to Convert Decimal Odds to Probability

If you want to find out the win probability of a given esports bet in the bookmaker’s assessment, just do it this way: 2.00 is exactly 50%. Anything below that is less than 50%. Anything above that is more than 50%.

The general formula for turning decimal odds to probability is this: 100/odds.

If a team’s odds of winning are 5.00, their estimated chance of winning is 20%.

Of course, all of this is true in the bookmaker’s assessment. But that doesn’t mean it’s 100% correct. In fact, sometimes you will find the real favorite regarded as the underdog, simply because the bookmaker doesn’t understand what’s going on. These are the situations in which you can make a lot of money.

Ultimately, you shouldn’t be worried about what the bookmaker is telling you and simply assess the situation yourself, using your own esports knowledge and seeking bets that give you good risk/reward ratios.

2. Fractional Odds

Fractional odds look like this: 5/1, 8/1, 2/1 and so on. Their general form is x/y, which means this: you make a profit of x dollars for every y dollars you wager.

So in the first example (5/1), you make $5 for every $1 you wager. And that’s just your profit. The total amount you get back is actually $6 (your profit plus the dollar you wagered).

Convert Fractional Odds To Percentage
Betway Fractional Odds

Just like with decimal odds, you’ll want to know how to convert odds to percentage and how to convert odds to probability.

Fractional Odds to Percentage

When turning fractional odds to percentage in order to calculate profitability, the general rule is to determine how many dollars you get for each dollar you wagered and then multiply that with 100. That will give you your profit in percentages.

So in the first case (5/1), you’d get a profit of 500%, while your total returns would be 600%.

But let’s take a more difficult example, such as 7/2. In this case, you’d get a profit of $7 for each $2 you wagered. To figure out the percentages, just divide 7 by 2 and then multiply with 100. What you’d get is 700/2 or 350%.

Fractional Odds to Probability

If you want to turn fractional odds to probability in order to figure out the win probability of a given team according to the esports betting site, just use the following formula: given the odds of n/m, the number you’re looking for can be found like this: (m/(m+n)) * 100.

For example: 4/1 would give us (1/(4+1)) * 100 or (1/5) * 100 or 100/5 or 20%.

3. American Odds

These types of odds are the most unusual and difficult to grasp at first because it’s hard to deduce what they mean unless someone explains them to you.

And their meaning is this: when you see the minus sign (-), that’s the favorite. And the number followed by it represents the amount you need to wager to make a profit of $100.

Convert American Odds To Percentage
American Odds

When you see the plus sign (+), that’s the underdog. And the number followed by it represents the profit you’ll make for every $100 you wager.

For example:

Team A: -760

Team B: +585

If you wanted to bet on team A, for each $760 you wagered you’d make a profit of $100, meaning that you’d get a total of $860 back.

If you wanted to bet on team B, for each $100 you wagered you’d make a profit of $585, meaning that you’d get a total of $685 back.

American Odds to Percentage

For underdogs, transforming American odds to percentage is simple: the odds themselves constitute the profit percentage. So in the above case, the percentage is 585%. Because you’re wagering $100 and making a profit of $585, So the percentage of the total return is actually 685%.

For favorites, what you do is this: you divide 10,000 by the number associated with them and you get the percentage you’re looking for.

In the example above, the result would be 10,000/760 = 13,15%. This would be your profit. So in total, you’d get back 113,15% of what you wagered.

American Odds to Probability

For the underdogs, the win probability can be obtained using the same method used for fractional odds.

So in our example, we’d have 5.85/1 and that would give us (1/(1+5.85)) * 100 or (1/6.85) * 100 or 100/6.85 or 14.6%. To calculate the win probability for the favorite, just subtract that from 100% and voila!

How do you Convert American Odds to Decimal Odds?

American odds are the same as money line odds, and they are often written as the amount you would win based on a $100 bet. A +400 American Odds bet would mean you win $400 for a $100 bet, meaning a total return of $500, meaning the bet odds is 4/1.

We also know that the decimal equivalent of the 4/1 bet is 5.00. However, you can also work out the decimal odds using the American odds alone. Simply add the stated odds to 100 and then divide the total by 100. (+400+100 = 500. 500/100 = 5, which equates to Decimal Odds of 5.00)

If you want to learn more about Dota 2 odds, League of Legends odds or any other kind of esports odds, just check out our guides!


How are Odds Calculated?

The odds on any betting market are calculated based on the number of probable outcomes and also the bookmakers’ margin on the bet, which should mean that regardless of the outcome of the event, the bookmaker should make a profit.

The easiest way to see how odds are calculated is via an example of an event with two possible outcomes of equal probability, such as the toss of a coin. The outcome of the coin toss being heads or tails is pretty much 50/50.

Logically, you would then think a bookmaker would offer even money on this bet, but they then have to build in their margin. Which means the odds offered will be slightly lower.

In this example, if the odds offered were 10/11 (1.91) on either Heads or Tails, this would mean that if you bet £10 on the outcome, you would win £9.10 for a total return of £19.10. The aim of the esportsbook is to balance their book by ensuring that they have enough betting on the other outcome to cover their liability and ensure they make a profit.

How do you Convert Odds on Money Line Bets?

When money line bets are shown as +300 or +1600 then the easy way to convert these into decimal odds or fractional odds is to remember that the odds shown are displayed as how much profit you would make on a $100 bet.

So, in the first example above a money line bet with odds of +300 would see a person placing $100 on that bet, win $300, for a $400 total return. This then translates into a bet of 3/1 (or 4.0 in decimal odds).

League of Legends

How Do You Calculate Probability From Odds?

There is a very simple calculation you can use to calculate the probability of your bet from the esports odds given.

The calculation is A / (A+B). In this calculation A is the player’s chance of winning, whereas B is the player’s chance of losing.

So let’s say that a player has placed a bet on a speedway race with four competitors. The player has backed one competitor to win, but there are three riders that the player has not backed that could cause them to lose.

Substituting these figures into the calculation gives us 1/(1+3) which can be simplified to 1/4. Therefore, a player’s chances of winning are 1/4 or 25%.

What happens if you bet $100 on a +140 Money Line?

If you bet $100 on a +140 money line bet and the bet is a winner, then you will receive back your $100 stake, plus $140 in winnings. This would mean a total return of $240. However, if your bet is a loser, then you would lose your stake and get nothing in return.


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