Fractional Odds | What Are Fractional Odds? How Do They Work?

Fractional odds, also known as traditional odds or British odds, represent the ratio of the amount that will be won relative to the amount staked. They are commonly used at Bookmakers operating the United Kingdom, Ireland, and other countries that follow the British betting tradition.

Fractional odds are expressed in the form of a fraction, such as 5/1, 3/2, or 7/4. The first number in the fraction represents the amount that will be won if the bettor places a stake equal to the second number. For example, if the odds are 5/1 and a bettor places a stake of £1, they will make a £5 profit if the bet is successful, plus they will get their original £1 stake back, resulting in a total payout of £6.

In the example of 7/4 fractional odds, the potential profit is not immediately intuitive. To work out the profit of any fractional odds bet, you can use a simple formula:

Profit = stake x (numerator / denominator)

Therefore a £2 bet at 7/4 stands to make a profit of £2 x (7 / 4) = £3.50, and a total return of £5.50 (£3.50 + £2 stake).

Fractional odds can be converted into percentages (known as implied probabilities) using the following formula:

Implied Probability = (denominator / (denominator + numerator)) x 100

Here, the denominator refers to the number on the right side of the fraction, and the numerator refers to the number on the left side of the fraction.

For example, let’s say you have fractional odds of 1/10, the implied probability of the event occurring is (10 / (10+1) x 100) = 0.909 = 90.90%.