Odds Converter: Decimal, American, Fraction & Probability

The decimal odds format is very easy to use and can be easily understood by beginners. This is why most odds comparison services, such as arbitrage wager spotter applications, use them as their default format both in the sure bet feed and in the arbitrage calculator.

To calculate the probability of a particular outcome using decimal format, divide 1 by the decimal odds. For example, if the quoted prices are 2.5, the probability of the outcome occurring is 1 / 2.5 = 0.4, or 40%.

Using mathematical formulas, decimal odds can also be easily converted into otherformats, such as fractional and Americans. This makes them a versatile choice for betting enthusiasts who want to compare odds across different formats.

How do you convert American to decimals?

To translate American to decimal odds, you can use the following formula:

Decimal = (American / 100) + 1

If the Moneyline is positive, you would divide by 100 and add 1. For example, if the quoted prices are +200, the calculation would be:

Decimal = (200 / 100) + 1 = 2.00

Under these prices, a $100 wager corresponds to a total payout of $300, including stake.

If the American is negative, the calculation would be slightly different. In this case, you would divide 100 by the absolute value of the quoted prices and then add 1. For example, if the odds are -150, the calculation would be:

Decimal = (100 / 150) + 1 = 1.67

This means a stake of $150 would return $250 in total if the outcome wins.

Overall, converting Moneyline to decimal odds is a straightforward process that can be useful for comparing them across different formats and calculating potential payouts for a particular wager.

Another use case is when using services such as the following value betting simulator.

How do you convert fractional to American?

To convert fractional to American odds, you can use the following formula:

American = ((numerator/denominator) + 1) x 100 if the fractional are below 2.

American = (-100) / ((denominator/numerator) – 1) if the fractional are 2 or greater.

Let’s take an example to understand this better. If the fractional odds are 4/1, you would divide 4 by 1 to get 4. Then, you would add 1 to get 5. Finally, you would multiply 5 by 100 to get the Moneyline, which would be +500.

Similarly, if the fractional odds are 5/2, you would divide 5 by 2 to get 2.5. Then, you would add 1 to get 3.5. Finally, you would multiply 3.5 by 100 to get the American of +350.

If the fractional odds are 1/2, you will divide 1 by 2 to get 0.5. Then, you would add 1 to get 1.5. Finally, you would multiply 1.5 by 100 to get the American of -200.

Converting fractional odds to Moneyline requires some calculation and is useful for comparing pricing across different formats and understanding payout structures.

How do you convert odds to probability percentages?

To translate odds to probability percentages, you can use the following formula:

Probability percentage = (1 / Decimal) x 100

For example, if the decimal odds are 2.5, you would divide 1 by 2.5 to get 0.4. Then, you would multiply 0.4 by 100 to get the probability percentage, which would be 40%.

Similarly, if the decimal is 1.8, you would divide 1 by 1.8 to get 0.56. Then, you would multiply 0.56 by 100 to get the probability percentage of 56%.

Suppose the quoted prices are represented in fractional or American format. In that case, you first need to convert them to decimal odds using the appropriate formula and then use the above formula to get the probability percentage.

Finding out the probability comes in handy when focusing on wagering techniques such as value betting or to use it in expected value calculators.

Probability calculations are also used in bankroll allocation models, such as the Kelly Criterion (check the calculator), which are often demonstrated through educational tools.

How do you convert probability percentages to odds?

To convert probability percentages to odds, you can use the following formula:

Decimal = (1 / Probability percentage) x 100

For example, if the probability percentage is 25%, you would divide 1 by 0.25 to get 4. Then, you would multiply 4 by 100 to get the decimal odds of 400.

Similarly, if the probability percentage is 60%, you would divide 1 by 0.60 to get 1.67. Then, you would multiply 1.67 by 100 to get the decimal of 167.

If you want to express in fractional or American format, you must convert the decimal using the appropriate formula.

How do you convert decimal format to Moneyline?

To translate decimal to Moneyline odds, you can use the following formula:

If the decimals are below 2, the Americans would be a positive number, which can be as:

American = (decimal – 1) x 100

For example, if the decimals are 1.80, you would first subtract 1 to get 0.80. Then, you would multiply 0.80 by 100 to get the American, which would be +80.

If the decimal odds are 2 or greater, the Moneyline would be a negative number, which can be as:

Moneyline = – (decimal – 1) x 100 / (decimal – 1)

For example, if the decimal are 3.50, you would first subtract 1 to get 2.50. Then, you would multiply 2.50 by 100 to get the numerator of the fraction, which would be -250. Finally, you would divide -250 by 2.50 to get the denominator of the fraction, which would be -100. So the American would be -250/-100 or +250.

You can round the result to the nearest integer to express the American odds as a whole number.

How to read betting odds?

The purpose of this article is to explain how betting odds represent probability and how different formats are interpreted and compared.

Understanding price formats and likelihood representation is essential for interpreting wagering markets.

With dedication, learning, and patience, bettors can better understand how they are structured and how probability impacts long-term outcomes. However, wagering always involves financial risk and outcomes are never guaranteed.

In sports betting, odds represent the statistical probability of a particular outcome. Depending on what country you are from, you may be familiar with the following, most common formats:

Fractional:

Fractionals are commonly used in the United Kingdom and Ireland, and you can also meet them on horse racing bets. But sure bettors in the UK and generally speaking outside of the US are using decimal odds.

Fractional formats express the net payout you get relative to your stake. As an example, the odds of 3/1 would mean that if you win the bet, you get a profit of 30$ if you place a 10$ stake.

At 1/5, the net return equals one-fifth of the wager amount.

Decimal:

These are most commonly used in other parts of Europe, Canada, Australia, and Singapore.

These at the payout include your stake too, so for example, with a price like 1.90, you place a stake of 100$ and if you win, the payout would be 190$, including your stake too, so with a profit of 90$.

Decimals are easy to understand and to use because they are the direct inverse of the probability of the outcome (an odd of 2, for example, has the probability of 1 / 2 = 50%).

In the world of sharp wagering, most of the time the decimal format is used, so in my examples I will stick to it too. Down below, you can see some examples of fractional and decimal, and their percentage format.

Fraction	Decimal	Implied Probability
1/5	1.2	83.3%
2/9	1.22	81.8%
1/4	1.25	80%
2/7	1.29	77.8%
1/3	1.33	75%
4/11	1.36	73.3%
4/9	1.44	69.2%
1/2	1.5	66.7%
1/1	2	50%
5/4	2.25	44.4%
9/1	10	10%
10/1	11	9.1%
20/1	21	4.8%

Source: Odds – Wikipedia