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Fractional Odds

Fractional Odds

Eric Kithinji
Eric Kithinji
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4 Min
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How To Read Fracional Odds
How To Calculate Winnings With Fracional Odds
How To Convert Fractional Odds

Sports betting odds are pretty regional. American sportsbooks tend to use American Odds, European markets and other markets around the world prefer decimal odds, while British bookmakers are fond of fractional odds.

As the name suggests, fractional odds are odds that are written in the form of fractions. Though this format may not be as straightforward as the other two, it’s definitely a quick and easy format once you become accustomed to it.

One major misconception that many people have regarding fractional odds is that they are extremely hard to read and understand.

So we’re going to bust this myth and show you how to read and understand fractional odds, which might be extremely handy if you find yourself in a situation where you’re forced to interact with such odds.

Understanding Fractional Odds

When you see odds written in the form of fractions— when one number on top of the other with a “/” in between them—you should immediately know that those odds are fractional odds.

4/5 is an example of a fractional odd. The bottom number, or the one to the right, represents the bet amount; while the top number, or the one to the left, represents your winnings.

So in our example, 5 is the bet amount while 4 is the amount that you’ll win. To put it simply, if you bet $5 with the above odds, you’ll win $4.

Others will often refer to the number on the left as the numerator and the number on the right as the denominator. When reading fractional odds out loud, we often start with the numerator then the denominator.

So 4/5 will be read as 4 to 5 odds, while 3/1 will be read as 3 to 1 odds. 1/1 is commonly referred to as “evens” because the bet amount and the winnings are of equal value.

Fractional odds will always be written as whole numbers. So instead of writing 3.5/1, a bookie will write that as 7/2.

Fractional odds are most commonly used in the United Kingdom and Ireland, and that’s why they are also called UK odds.

Calculating Winnings With Fractional Odds

Though many people think it’s hard, calculating your winnings using fractional odds is extremely easy. We’re going to show you several examples to prove to you how easy it is to calculate your winnings.

TeamFractional OddsAmerican OddsDecimal OddsBet AmountTo WinTotal Payout
LA Galaxy5/6-1201.83$100$83.33$183.33
LA FC6/5+1202.20$100$ 120$220

For example, let’s say that you want to place a bet on the above MLS game. You have your eyes on the LA Galaxy, and the team is priced at 5/6 (-120).

The simple formula that you need to use is this one:

(Numerator x Bet amount) ÷ Denominator = Winnings

So if you’re betting $100 on LA Galaxy, here’s what that bet would look like:

(5 x $100) ÷ 6 = $83.33

So your winnings will be $83.33, and your total payout will be $183.33 after your original stake of $100 has been included by the bookies.

If someone else chooses to bet $100 on Los Angeles FC, their winnings will be calculated in the following way:

(6 x $100) ÷ 5 = $120

So they’ll win $120, and their total payout will be $220 after the sportsbook includes the person’s original $100 bet amount.

You don’t need to worry about mastering any formulas since all sportsbooks will calculate your winnings automatically.

With time, after you’ve interacted with fractional odds long enough, you’ll be able to calculate your winnings instinctively without referring to any mathematical formulas.

Converting Fractional Odds To Implied Probability

Implied probability is a percentage that shows the likelihood of an event happening based on the sportsbook’s odds. Something that has a high probability has a greater chance of happening, so a higher percentage correlates to a greater probability.

On the other hand, if something has a low probability, the chances of that thing happening are lower, and it will thus have a lower probability percentage.

However, don’t make a wager simply because an event has a higher probability; you must consider other things first.

Converting fractional odds to implied probability is easy because there is only one conversion formula. So when you want to know the implied probability of an event, here’s the formula that you need to use:

Fractional Odds Implied Probability = (1 ÷ ((Fractional Odds) + 1)) x 100

So if we refer to our previous example, we can get the implied probability of both the Galaxy and Los Angeles FC.

LA Galaxy’s Odds = 5/6

LA Galaxy’s Implied Probability = (1 ÷ ((5/6) + 1)) x 100 = 54.55%

Los Angeles FC’s Odds = 6/5

Los Angeles FC’s Implied Probability = (1 ÷ ((6/5) + 1)) x 100 = 45.45%

This is just an example, but in real-life scenarios, when you add the implied probability of two teams, it will always be greater than 100%.

This is because sportsbooks always include a commission that is commonly known as the vigorish (or simply, the vig), which is the main way that sportsbooks make their money.

Converting Fractional Odds To American Odds

You may find yourself in a scenario where you’re forced to deal with fractional odds. If you don’t like the format, you can change to American betting odds by either opting for an online odds converter or by taking matters into your own hands through the use of conversion formulas.

So if you want to convert fractional odds to American odds, here are the two formulas that you can use:

When a numerator is greater than the denominator: Fractional odds x 100 = Positive American odds

For example, let’s convert 7/2 to American odds.

7/2 x 100 = +350

When the denominator is greater than the numerator: (-100) ÷ (Fractional odds) = Negative American odds

For example, let’s convert 1/2 to American odds.

(-100) ÷ (1/2) = -200

Converting American Odds To Fractional Odds

On the other hand, you may prefer fractions to positive and negative signs. So if you want to ditch American odds and use fractional odds going forward, here is how you can do so:

When dealing with positive odds, use this formula: Positive odds ÷ 100 = Fractional odds

Let’s convert +200 to fractional odds.

200 ÷ 100 = 2/1

When dealing with negative odds, this is the formula that you should use:

-100 ÷ Negative odds = Fractional odds

Let’s convert -200 to fractional odds.

-100 ÷ -200 = 1/2

When you continue to wager frequently, you’ll easily know how to convert odds in your mind without using any formulas or online converters.

Converting Fractional Odds To Decimal Odds

Many sportsbooks also prefer the use of decimal betting odds. If you want to convert fractional odds to decimal odds, here’s the formula that you need to use:

Divide the fractional odds, then add 1.

So 4/5, when converted to decimal odds, will be:

(4÷5) + 1 = 1.8

Converting Decimal Odds To Fractional Odds

When converting decimal odds to fractional odds, here’s the formula that most bettors use:

Subtract 1 from the decimal odds, then turn the decimal into a simplified fraction.

Keep in mind that if you get an improper fraction—when the numerator is greater than the denominator—you should keep it that way instead of turning it into a mixed fraction.

So if we wanted to convert 3.50 to fractional odds, here’s the simple procedure:

3.50 – 1 = 2.5

2.5 is the decimal equivalent of 5/2, so 3.50 in fractional odds will be 5/2.

Fractional Vs. American Vs. Decimal Odds

All odds have their own benefits, and most bettors have a preference for a certain format. So, ultimately, whether one format is greater than the other is just a matter of personal choice.

So if you think that fractional odds are better than the other two formats, or if you find that your brain computes fractional odds with ease, you can freely opt for that format.

Since many sportsbooks give users the freedom to choose, you can switch between fractional odds and American odds without any hassle.

Thirsty For More Betting Knowledge? Check Our Gambling Education Hub.


About the author

Placed his first sports wager shortly after high school, and has been involved in this whirlwind of the industry since then. Fan of most of the major ...

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