Fractional Odds - A Simple Introduction

Fractional odds are often used in the UK and Ireland, and sometimes they are also called traditional odds. When you look at fractional odds for the first time, they may look a bit confusing especially since there are so many different numbers involved. However, after reading this guide, you will know exactly how fractional odds work, understand what they mean and be able to place your bet with greater confidence.

Fractional Odds

Fractional odds show you how much you will get back for the bet you have played. The number to the left of the fraction shows the profit you can get if you play for the amount to the right of the fraction.


Fractional odds of 4/1, read as four to one, mean that you will receive four double profits for each unit you bet. In this example, if you bet £ 10, you will win £ 40 plus your bet of £ 10 and it gives you a total of £ 50.

Another example of fractional odds is 5/2. Although the number to the right of the faction has changed, the same principles apply. So, if you bet 2 GBP at odds that are 5/2 you will potentially be able to receive 5 GBP in winnings. Plus, you get back your original £ 2 bet.

Reversed fractional odds

At times, you may also see fractional odds, which appear to be reversed. For example, you can see odds of 1/4 or 2/5. These odds refer to "odds on" and occur when something is very likely to happen, such as the big favorite winning a football game. Arsenal will therefore have odds 1/4 in the match against Colchester in the FA Cup. Under these circumstances, you need to set GBP 40 to earn $10. Thus, you can see how these have been reversed in relation to odds 4/1, which we talked about in the section above.

Odds against

By looking at the examples above, 4/1 means that something is less likely to occur. Odds of 2/1 or 1/4 are the opposite. A good rule of thumb when it comes to fractional odds is that if the number on the left side of the fraction is greater than the number on the right, something is less likely. This is also known as "odds against".


You can also see fractional odds stated as 1/1, which is also known as even odds. Even odds mean you will get back the same amount as your bet. For example, if you placed £ 10 on odds of 1/1, you will receive £ 10 in winnings plus your original bet of £ 10, ie a doubling of your money. Therefore, you can look at fractional odds of 1/1, as a way to double your bet.


When it comes to using fractional odds to determine the likelihood that something will actually happen, there is a simple calculation method that you can use.

Take the odds 4/1, as used in the examples above. To calculate the possibility of this occurring, complete the following calculation: 1 / (4 + 1) = 0.20. In other words, there is a 20% chance that this outcome will become a reality.

Similarly, you can also calculate the probability of 1/4: 4 / (4 + 1) = 0.80. In other words, there is an 80% chance of this outcome becoming a reality.


Now we have given you a good understanding of fractional odds and what they mean. Below you will find a summary of the key points. These you can easily get back to when you need them.

  • The number to the left of the fraction shows the profit you can receive if you bet the amount to the right of the fraction
  • Betting on 4/1 will earn £ 40 in profits for a £ 10 bet, plus you will get the bet back
  • Betting on 1/4 will give you £ 10 for a bet of £ 40, plus you will get the wager back
  • If the number to the left of the fraction is greater than the number to the right, the outcome is less likely.
  • Odds of 1/1, or even odds, mean you will get back the same amount you wagered