If you’re just starting with sports betting or want to improve your knowledge, it’s really important to understand how betting odds function. Betting odds show not only how much money you might win but also how likely it is for a certain outcome to happen. Around the globe, there are three main types of betting odds formats: fractional, decimal, and moneyline (American). Each format presents potential returns and implied probability in its own way, and being able to read them is crucial for anyone who wants to make smart bets.
In this article, we will explain these three formats and show you how to use them effectively.
Table of Contents
Betting Odds Explained – fractional, decimal, and moneyline
1. Fractional Odds
Where you’ll find them:
Fractional odds are most popular in the United Kingdom and Ireland and are commonly used by bookmakers for horse racing, football, and other major sports.
How they work:
Fractional odds are displayed as two numbers separated by a slash (e.g., 5/1 or 10/3). The number on the left shows how much you’ll win relative to the number on the right, which is your stake.
Example:
If you bet £10 on a team at 5/1 odds:
You would win £50 (5 × £10) if your bet is successful.
You would also get your original £10 stake back, making your total return £60.
Implied Probability Calculation:
To calculate the implied probability:
Formula: Denominator / (Denominator + Numerator) × 100
Example: 5/1 odds → 1 / (5 + 1) = 0.1667 → 16.67% chance of winning.
2. Decimal Odds
Where you’ll find them:
Decimal odds are widely used across Europe, Canada, Australia, and increasingly in online sportsbooks worldwide due to their simplicity.
How they work:
Displayed as a single number with two decimal places (e.g., 6.00 or 3.50), decimal odds represent the total amount you’ll receive for every unit wagered — including your original stake.
Example:
If you bet £10 at 6.00 odds:
Your total return would be £60 (£10 × 6.00).
This includes your £50 profit and your £10 stake.
Implied Probability Calculation:
To calculate the implied probability:
Formula: 1 / Decimal Odds × 100
Example: 6.00 odds → 1 / 6.00 = 0.1667 → 16.67% chance of winning.
Decimal odds are generally considered more straightforward than fractional odds because you can instantly see your total return by multiplying your stake by the odds.
3. Moneyline (American) Odds
Where you’ll find them:
Moneyline odds are the standard format in the United States, used for sports like American football, baseball, basketball, and more.
How they work:
There are two types of moneyline odds:
Positive (+): Indicates how much profit you’ll make on a $100 bet.
Negative (−): Indicates how much you need to bet to win $100.
Example:
+500 odds: A $100 bet would win $500 profit (total return: $600).
−200 odds: You’d need to bet $200 to win $100 (total return: $300).
Implied Probability Calculation:
For positive odds:
Formula: 100 / (Odds + 100) × 100
Example: +500 → 100 / (500 + 100) = 0.1667 → 16.67%
For negative odds:
Formula: Odds / (Odds + 100) × 100
Example: −200 → 200 / (200 + 100) = 0.6667 → 66.67%
Moneyline odds can seem confusing at first, but once you understand whether you’re looking at a favorite (negative) or an underdog (positive), it becomes much easier to calculate potential returns and probability.
Many online sportsbooks allow you to pick your favorite odds format in your account settings or on your betting slip. Fractional odds have a long history, especially in the UK, but many people like decimal odds because they are clearer and easier to work with. Moneyline odds are different, but they are simple to understand once you know how they show favorites and underdogs.
Here are some tips for bettors:
Always check the odds at different sportsbooks.
Learn about implied probability to see the value in your bets.
Pick an odds format that you feel most comfortable with, especially if you are betting live or on several markets.
Beat the Bookies with Asian Handicap Power Picks
