Betting can be fun if done right. But if you’re not a math guru, betting odds presented as fractions, decimals, and negative numbers can seem a little intimidating.
That ends today! Reading this guide will equip you with the knowledge to calculate any betting odds you encounter in 2024 and beyond.
Calculating the different types of betting odds
You will encounter different ways of expressing odds. Each will have its own way of calculating the odds, as highlighted below:
Decimal
This is the simplest to understand and calculate. Most online sportsbooks use decimal odds by default. Decimal odds are shown as a number, say 3.50. This number shows how much you get back for every dollar you bet.
For example, if you bet $100 and the odds are 3.50, you’ll win $350 in total. That’s $250 profit plus your original $100. Use this formula to calculate decimal odds:
Profit = (Stake X Odds) – Stake
Here’s how to work out a stake of $70 at 1.5 decimal odds:
Profit = (70 X 1.50) – 70
Profit = 105 – 70
Profit = $35
Fractional
Fractional odds show how much profit you can make compared to your bet, represented as fractions, such as 3/1 or 5/2. The first number is the profit you’ll make, and the second is your stake.
For instance, if the odds are 1/5 and you bet $100, you’ll win $20 in profit (1/5 of $100). Your total payout will be $120 (your $100 bet plus $20 profit). Use this formula to calculate fractional odds:
Payout = (Stake ÷ Denominator) X Numerator
Here’s an illustration using a $50 stake for a winning team with 3/2 fractional odds:
Payout = (50 ÷ 2) X 3
Payout = (25) X 3
Payout = $75
To find your profit:
Profit = Payout – Stake
Profit = 75 – 50
Profit = $25
Fractional odds are popular in Europe, especially for horse racing in the UK and sometimes for Daytona 500 betting.
American/Moneyline
This is the most challenging for most bettors but can be easily understood if you take the time to learn. The moneyline or American odds are represented with a plus (+) or minus (-) sign, such as -150 or +130. A minus (-) means you must bet that amount to win $100, while a plus (+) means you’ll win that amount if you bet $100.
Usually, one team has +odds (the underdog), and the other has -odds (the favorite). Sometimes, both teams can have -odds; in that case, the team with the number farther from zero (like -140 vs. -105 for the opposition) is the favorite.
To calculate negative moneyline odds, use this formula:
Profit = (Stake ÷ Odds) X 100
For example, betting $75 on a winning team with -150 odds
Profit = (75 ÷ 150) X 100
Profit = 0.5 X 100
Profit = 50
In this instance, your total payout will be profit ($50) + stake $75 = $125.
Use this formula to calculate positive moneyline odds:
Profit = (Stake X Odds) ÷ 100
So, if you bet $70 on a winning team with +150 odds, this is how to go about it:
Profit = (70 X 150) ÷ 100
Profit = 10,500 ÷ 100
Profit = $105
Therefore, your payout will be profit ($105) + stake ($70) = $175.
Popular bet types calculations
Different bet types have different compositions and are calculated differently:
Accumulator bets
An accumulator bet combines several bets into one. To win, all the individual bets in the accumulator must win.
It’s easiest to calculate using decimal odds. If your bookmaker uses fractional or moneyline odds, you can convert them to decimal odds first (we’ll explain how later).
To find the total odds for an accumulator, use this formula:
(Multiply all odds) X Stake
For instance, if you combine the odds of these five teams:
- Arsenal – 2.6
- Chelsea – 1.4
- Liverpool – 2.2
- Manchester City – 1.8
- Manchester United – 4.2
If they all win, your payout for a $15 stake will be:
Payout = (2.6 X 1.4 X 2.2 X 1.8 X 4.2) X 15
Payout = 60.54 X 15
Payout = $908.10
Converting to preferred format
As we said, it is easier to calculate accumulator bets using decimal odds. Use these formulas to convert from other formats:
From moneyline odds to decimal odds
If it’s a positive moneyline, the formula is:
(moneyline ÷ 100) + 1
So for a +150 moneyline:
= (150 ÷ 100) + 1
= 1.5 + 1
= 2.5
The formula for a negative moneyline:
(100 ÷ moneyline) + 1
Illustration using a -250 moneyline:
= (100 ÷ 250) + 1
= 0.4 + 1
= 1.4
From fractional odds to decimal odds
Divide the first number by the second, then add 1.
For instance, converting fractional odds of 1/5 would go something like this:
= (1 ÷ 5) + 1
= 0.2 + 1
= 1.2
Convert decimal odds to fractional or American odds
To convert decimal to fractional odds, subtract 1 from the decimal, then convert it to a fraction.
Example using decimal odd 3.5:
3.5 – 1 = 2.5
2.5 converted to decimal = 5/2
To convert decimal odds to moneyline odds:
- If the decimal odd is greater than 2, use this formula = 100 X (Decimal odd – 1)
- For decimal odds less than 2 = (Decimal odd – 1) X –100.
Using a sports betting calculator
If calculating the odds seems like too much work, there’s a solution for this: a sports betting calculator. Using one simplifies the whole process of computing betting odds and eliminates the chances of calculation errors.
There are plenty of sports betting calculators in the market. Most combine the calculations for all the different types of betting odds. Just search Google Play or the Apple App Store. Alternatively, navigate to one of the many betting calculator websites to find one suited to your needs.
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