How Do Betting Odds Work?

Understanding how betting odds work is critical when it comes to sports betting since they help you understand how likely something is to occur and what your winning potential is.


Step One: Defining Probability

For any given event, be it an MMA fight, an F1 Grand Prix, a Horse Race, an NRL game, or a Basketball match, there are a set number of possible outcomes. Betting odds give you a number which represents these, in various formats, including decimal and fractional.

When you see two numbers separated by a trailing slash, you are looking at fractional Odds. A quick calculation using these integers will tell you how likely X is to occur, Probability, or %, = B / (A+B). So, if you’re looking at 9/1, the sum will become 1 / (9 + 1) = 0.1, so there is a 10% chance that X will occur.

Now that you know how to work out the probability that something will happen, you can move on to figuring out how much money you can win with the given betting odds.

Step Two: Calculating Wins via Betting Odds

To put it simply, let’s once again turn 9/1 into A/B. For every value of B that you wager, you will win A, along with the amount you staked in fractional odds. So, for every $1 you bet, in this example, you will win $9 back.

Step Three: Bringing Decimals In To Your Calculations

Decimal odds are more commonly used than fractional odds, so it’s important that you become familiar with them too. You will be glad to hear that they’re easier to work out!

The calculation here is winnings = (odds X stake) – stake, so, in our example, 9.0 works out to (9.0 X $10 stake) – $10 stake = $80 winnings.

But don’t stress out too much if this is taking a little time for you to get the hang of since there are many bet calculators available online that will work out the numbers for you if you need them to. And you can be sure that you’ll find yourself understanding them more and more easily as you gain experience wagering.

Decimal Versus Fractional Odds

While neither format is really better than the other, there is definitely a trend emerging which sees decimal odds being favoured. Historically, fractional odds were the top pick for bookmakers in the United Kingdom but because decimal odds are so much easier to understand, online sportsbooks tend to provide them almost unanimously nowadays.

The major difference between the two formats is that fractional odds only represent winnings, they don’t include the return of your stake, and decimals do, so the latter group gives bettors a much more accurate idea of what they can expect to see in their pockets at the end of the day.

The enormous popularity of betting exchanges can also be linked to the increased use of decimal odds just as NRL premiership odds has to offer. When odds change just slightly it’s tough to alter probabilities marginally without creating huge fractions which can boggle bettors’ brains!