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

Fractional odds represent the potential profit of a bet relative to the stake, expressed as a fraction.

What Are Fractional Odds?

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 in 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%.

Example 1

Liverpool to win against Manchester United at odds of 4/5 with a stake of £50:

  • Return = (stake x (numerator / denominator)) + stake = (£50 x (4 / 5)) + £50 = £90
  • Profit = return – stake = £90 – £50 = £40

Example 2

Tiger Woods to win the US Masters at odds of 5/1 with a stake of £25:

  • Return = (stake x (numerator / denominator)) + stake = (£25 x (5 / 1)) + £25 = £150
  • Profit = return – stake = £150 – £25 = £125

Example 3

Serena Williams to win Wimbledon at odds of 2/1 with a stake of £100:

  • Return = (stake x (numerator / denominator)) + stake = (£100 x (2 / 1) + £100 = £300
  • Profit = return – stake = £300 – £100 = £200

Pros & Cons of Fractional Odds

Here are some of the pros and cons of using fractional odds:

Pros

Widely Used In the UK

Fractional odds are the most common odds format used in the UK. Once you grasp the format, betting at British bookmakers becomes a lot simpler.

Easy to Understand

Fractional odds are relatively simple to understand, even for novice bettors. They represent the ratio of the potential payout to the original stake.

Clear Indication of Potential Profits

Fractional odds provide a clear indication of the potential profits from a bet. For example, if the odds are 2/1, you will win £2 for every £1 you bet.

Cons

Confusing for Non-UK Bettors

Fractional odds can be confusing and difficult to understand for bettors who are accustomed to using another format.

Less Precise Than Decimal Odds

Fractional odds are less precise than decimal odds, which means value can be lost due to rounding.

Uncommon On Betting Exchanges

Fractional odds are used for fixed-odds betting at bookmakers and aren't available at all betting exchanges. This means you'll need to learn decimals if you want to start trading.

More Odds Formats

Michael Anderson
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