Betting Odds Explained

by Fractions
Updated: 27/08/2020 10:46

If you are new to betting or do not understand betting odds this is a must-read guide. Yes, you can use a bet calculator to work out your returns, but you need to learn how to identify value in a bet. It is also critical in working out the probability of an event occurring which allows you to see if there is value in the betting odds available.

In this guide, we will explain the three most popular odds formats, Fractional odds, Decimal odds & American odds, while also teaching you how to convert the odds into a percentage, that allows you to see if there is value in the odds available.

Fractional, decimal and American odds are simply just different ways of presenting the same odds and have no difference in terms of the payouts. We recommend using the odds format in which you can easily convert to a percentage, and work out your return. For us, that is the decimal odds format.

After reading this guide you will be able to compare odds across different betting sites no matter the format. Also, we independently test the betting margins of each bookmaker to see how much each bookie “charges” to place a bet.

How do Betting Odds Work?

In short, betting odds represent the probability of an event occurring. Depending on which odds format you use, you will know how much you need to stake to win a certain amount, and how much you will win overall (including stake) if the bet is successful.

As an example, 2/1 fractional odds mean for every £1 you stake, you will win £2.

Fractional Betting Odds Explained

Fractional betting odds are most common in the UK, but most UK bookies now offer several different formats. But if there are only fractional betting odds, it’s easy to understand.

The easiest way to learn is by looking at the odds like this: How much you will win/how much you stake (2/1)

So for every £1, you stake, you will win £2. Simple as that. (2/1)

8/1 = Every £1 you stake, you will win £8

1/10 = Every £10 you stake, you will win £1

1/3 = Every £3 you stake, you will win £1

1/1 = Every £1 you stake, you will £1

This is not including your stake though, just the profit from the bet. For the total amount add your stake.

Decimal Betting Odds Explained

Decimals betting odds are becoming a lot more popular, and almost all bookies now have them as an option. They are an alternative to fractions and can be easier to work out the overall return (including your stake) and easier to convert into a percentage.

Our free football betting tips are listed in the decimal format as it is the easiest method of calculating returns. They represent the potential returns of the bet including the stake.

Simply multiply the amount you wish to bet by the decimal odds offered.

Calculation: (odds x stake = returns – stake = profit)


3.50 x £10 = £35 – £10 = £25 profit

2.00 x £10 = £20 – £10 = £10 profit

1.10 x £10 = £11 – £10 = £1 profit

Betting Odds as American

American odds, also known as Moneyline odds are shown in a positive or negative number. A positive number shows how much you might profit if you bet £100.

A negative number shows what you must bet to make £100 profit. The positive number shows the underdog and the negative shows the favourite.

This format will not be used by many UK punters but it is an option in many sportsbooks so it’s good to know.

Now it’s important to know that you do not need to bet £100, the odds work on whatever stake you place.

American Odds: Russia (-275) vs Saudi Arabia (+900) stake £100

To work out the favourite you can do 100 / 275 x 100 = £36.36 profit with your £100 stake

To work out the underdog you can do 900 x 100 / 100 = £900 profit with your £100 stake

Working Out Betting Odds as a Percentage

Bear in mind that the odds reflect the chance of a said event happening. It is important to know how to change it to a percentage to see if there is any value in the betting odds. The easiest way is using the decimal odds.

Quite simply divide 100 by the decimal odds and you have the %.


100/1.40 = 71%

100/2.00 = 50%

100/3.50 = 28%

As you can see the lower the decimal the higher the percentage and vice versa. Of course, just seeing this percentage does not help you know if there is value in the bet. You will still need to compare match stats or the market stats for the event of your choice.

For example, if over 2.5 goals have landed in both teams last matches 5/10 (50%) times. Odds over 2.00 (over 50%) could be seen as good value. Of course, there are many more factors that can decide if a bet has good value, but it is a good start.

Steven is the product manager on BettingLounge and enjoys enhancing sporting events through betting for long-term, sustainable profit.


  1. Tom 07/01/2019 08:53

    I only ever used fractions as they are so common in England, but the decimals make so much more sense after reading this!

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