Betting on online casinos is entirely dependent on betting odds. If you want to be a successful bettor you have to understand the concept of chance.

Simply put, a chance is the likelihood of an event happening. Often referred to as probability it is represented in percentages.

For instance, the roll of a dice has a 1/6 probability for each outcome i.e. 1 out of 6. In percentage, this probability is 16.66% for every outcome.


What exactly are betting odds? 

Betting odds are nothing but the likelihood of an event to occur during a game. Interestingly there are several variations of betting odds into existence. While all forms of betting odds have the same implied probabilities, they are represented differently that might confuse you.

Knowing how to convert betting odds can be a very helpful skill for bettors. There are online odd converter tools to do the calculation and conversion for you, but understanding the concept behind will just make you a better bettor.

Sportsbooks offer betting odds in 3 formats-Decimal Odds, Fractional Odds, American Odds.

Let’s find out how to convert each into its implied probability.


Converting Decimal Odds

Most preferred by the online sportsbooks, decimal odds are simply the reflection of the return a punter will receive for each unit placed. Let’s say a matchbook is offering you soccer odds of 1.50 for Real Madrid to win. It implies that for every 1.00 unit you bet, you will get a profit of 0.50 should Madrid win.

Simple calculation to convert decimal odds to implied probability:

Implied probability = 1 / “Decimal Odds”

If we have to convert the above decimal odds to implied probability, then:

1 / 1.50 = 0.666 (multiplied with 100 to convert to implied probability) = 66.6%


Converting Fractional odds

The most traditional form of expressing betting odds, they simply represent the return for a particular amount you bet.

For example, if you find a sportsbook offering you 5/3 odds (5 to 3) for Manchester United to win. It implies that for every 3 units you bet you will get 5 back as profit. That is, if you bet $30 and Manchester wins, you will receive $50 in addition to your stake of $30.

Converting fractional odds to implied probability:

Implied probability = denominator / (denominator + numerator)

For the above example:

5 / 3 = 3/ (3+ 5) = 3/8 = 0.375 (multiplied with 100) = 37.5%

You cna use this formula to convert calculate the best odds online.


Converting American Odds

American odds is what most veteran bettors in the US stubbornly stick too. Not so popular outside North America, these odds are also known as Moneyline odds.

There are two instances of American Odds: Minus (-) and Plus (+).


Let’s take minus American odds first. If a bookmaker is offering you a -120 for Brazil to win, it essentially says that you will have to bet $120 to win $100.

The plus American odds are expressed as +120. Now in the same scenario as above, a ‘+’ odds indicate that you will win $120 if you bet $100.

Converting ‘minus’ American odds into implied probability:

Implied probability = ( – ( ‘minus’ American odds ) ) / ( – ( ‘minus’ American odds ) ) + 100

For instance, if we convert the above odd into its implied probability

(- (-120) / ( (- (-120) ) + 100) = 120 / 220 = 0.545 (multiplied by hundred) = 54.5%

Converting the same plus American odds into implied probability:

Implied probability = 100 / ( ‘plus’ American odds + 100 )

That is:

( 100 / 120 + 100 ) = 100 / 220 = 0.4545 (multiplied by 100) = 45.45%



Implied probability does provide a straightforward method for risk analysis but most sportsbooks don’t offer you the same. We hope our quick guide will help you with the respective conversions.