Converting sports betting odds is a fundamental skill that all bettors should have. While most sportsbooks offer the ability to quickly change between the three most common odds formats, once you start diving into more complex situations, knowing how to convert odds will be an invaluable skill.
This article will show you how to read American, decimal, and fractional odds. We’ll also provide the formulas to convert between all the odds types, and give you a path to strengthen your understanding of core betting concepts.
If you’ve ever looked at a sportsbook’s lines before, you’ve probably noticed that there are a few different ways to view the odds. The three most common odds formats most in-person and online sportsbooks use are American, decimal, and fractional.
American odds are displayed as a + or -, where plus indicates an underdog wager, while negative is the favorite.
If you look at the moneyline odds, you’ll see the Cubs are the underdogs at +126, while the Pirates are the favorites at -140.
The odds present a hypothetical payout. For example, betting $100 on the Cubs would return $126 plus your original $100 wager. Betting on the Pirates, since they are the favorite, means you’d have to bet $140 to return $100 profit.
Decimal odds are common in Europe and Canada, and do not have the same formatting that American odds have. Instead, decimal odds show you how much you’d return in stake plus profit.
In this scenario, you can see that betting $100 on the Cubs would return you $226 ($100 bet returned and $126 profit). On the flip side, betting $100 on the Pirates would return you $171 ($100 stake and $71 profit).
Decimal odds are easier to understand at first glance than American odds, because it accounts for profit and stake returned. You can tell which team is the favorite by the first number. If it’s a 1, like in the above example, the team is the favorite.
Fractional odds aren’t as popular as decimal or American, mainly because they’re a bit more confusing to read.
Fractional odds show you how much you’ll win relative to your stake. For example, betting on the Cubs (5/4) would net you $5 profit on a $4 stake. So, if you were to bet $20 on the Cubs, you’d net $25 profit.
You can tell which team is the underdog if the numerator is greater than the denominator. And if the denominator is greater than the numerator, like with the Pirates moneyline (13/18), that team is the favorite.
Converting Odds for Simplified BettingMost sportsbooks allow you to easily switch between your preferred odds type. But, if they don’t, the formulas aren’t difficult to learn. Below, I’ll show you how to switch between all the odds types with simple formulas.
There are two different formulas to convert American odds to decimal odds:
Negative American Odds: Decimal = (100/American odds) + 1
Positive American Odds: Decimal = (American Odds/100) + 1
There are also two formulas for converting American odds to Fractional odds, depending on whether the odds are positive or negative.
Negative American Odds: Fractional = 100/American Odds
Positive American Odds: Fractional = American Odds / 100
There is only one formula for converting fractional odds to decimal odds.
Decimal Odds = (Numerator / Denominator) + 1
Converting from fractional to American odds is a bit more complex, to account for the underdog/favorite.
Fractional Odds Greater than 1/1 (Underdogs): American Odds = (Numerator / Denominator) x 100
Fractional Odds Less than 1/1 (Favorites): American Odds = – (Numerator / Denominator) x 100
Similarly, there are two formulas for converting underdogs and favorites to American odds.
Decimal Odds Less than 2.00 (Underdogs): American Odds = (Decimal – 1) x 100
Decimal Odds Greater than 2.00 (Favorites): American Odds = -100 / (Decimal – 1)
There’s only one formula to convert decimal odds to fractional odds. The hardest part is converting the decimal odds without stake added to a fraction.
Fractional Odds = (Decimal Odds – 1) as a fraction
Why learn how to convert odds? Well, when you start to develop other sports betting skills, such as identifying implied probability, using the decimal format makes the process much easier.
Once you’ve learned how to convert odds, you can start with more complex calculations.
How to Convert Odds to Probability – Using the given odds of a wager, you can identify what the sportsbook predicts will happen. This is called implied probability, and is a building block for finding the expected value of a wager.
Using Odds and Probability to Find EV – The expected value is an actual estimation of how profitable a wager is, and is more complex than the simple stake/profit you identified with implied probability. Smart betters know how to leverage EV to make more profitable wagers over the long-term.
For casual bettors, American odds will be the most common type of betting odds you’ll use. But, there’s a clear benefit to using decimal odds, and that’s the stake included in the final odds value. If you’re betting serious money on NFL, MLB, or NBA games, consider switching your odds format to decimal for a better visual representation of value.
Plus, getting used to decimal odds will set you up for success when you start diving into more advanced topics.
If you start good habits now, such as learning how to read all betting odds types, you’ll be a sports-betting whiz in no time.
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