How Betting Odds Work

In betting there are three main ways of displaying odds, they are Fractions, Decimals and American. They all are a different way of representing the same thing, that is, the probability of something happening. 

It’s important to understand these and how they work to get the full value from Predict-O-Vision. We use ‘implied probability’ to make our predictions, we explain the relationship between this and the bookies odds below. 


What Makes a Bet a Good Bet - The Kit Man’s Recommended Approach 

  1. Switch from Fractional to Decimal odds in your bookmakers apps - this will allow you to quickly and easily compare what the bookies odds are versus the prediction we’ve made using data. It’s very easy to change the settings in your preferred bookies account from Fractional to Decimal. We highly recommend it, you’ll quickly get used to the change and wonder how you used to manage with Fractional!
  2. After running your chosen predicted percentage through the calculator (found at the bottom of the Predict-O-Vision page) you’ll get your decimal value. 
  3. If you compare this to the bookies odds and find that the DataVision prediction decimal is lower than the bookies (i.e. closer to 1.00) then you’ve found your edge. This means that DataVision is expecting the outcome to be more likely than the bookies and they’re “over paying” with their odds.
  4. The greater the difference, the greater your edge and your potential return.


Fractional Odds (also known as ‘British odds’, ‘UK odds’, or ‘traditional odds’)

If you’re from the UK or Ireland you will be used to seeing the fraction format. This shows you the return should your bet come in and is displayed using fractions, e.g. ‘2/1’. This means that for every £1 wagered, you are getting £2 back when a bet comes through. 

This is quite easy when the fraction is 2/1 or 3/1 but does get tricky when it’s something like 17/20. In this case, an easy way to quickly work out potential returns is to look at the numerator (the top number) and denominator (the bottom number), the return is £17 for every £20 wagered.

Fractional odds are used by all of the well-known and largest bookmakers which makes them the preferred odds worldwide.

Total Payout = [Stake x (Numerator/Denominator)] + Stake where numerator/denominator is the fractional odd, e.g. 4/1.

Giggs Celebration


Decimal Odds (also known as ‘European odds’, ‘digital odds’, or ‘continental odds’)

You’re more likely to encounter this approach in Europe, Australia, New Zealand, and Canada. 

Generally they’re seen to be a bit more straightforward. The favourites and underdogs can be spotted instantaneously by looking at the numbers. That is simply because the higher the total payout (i.e. the higher the decimal), the less probable (and riskier) it is for a certain outcome to happen. For example 1.8 (favourites) vs. 3.4 (underdogs). 

Simply put, the decimal odds number represents the potential return should the bet succeed, relative to the stake, or the amount a win returns for every £1 wagered. For example, imagine Burnley had odds of winning a particular match of 2.5. If you bet £10 on Burnley and they won, you would get a total payout of £25 (£10 x 2.5). The return includes the initial stake of £10, giving a net profit of £15.

Total Payout = Stake x Decimal Odd Number

American Odds (also known as ‘moneyline odds’ or ‘US odds’)

Unsurprisingly, this is the most popular odds format in America. Here, the odds for favorites are accompanied by a minus (-) sign (e.g. ‘-452’, ‘-381’), and indicates the amount you need to stake to win £100. On the other hand, the odds for underdogs are preceded by a positive (+) sign (‘220’, ‘182’), indicating the amount that you would win for every £100 staked. In both positive and negative odds bets, you get your initial wager back alongside the amount won. 

Another way of looking at this is:

  • Positive figures: odds of 110 would win £110 on a £100 bet.
  • Negative figures: odds of -120 would win £100 on a £120 bet.


But where does Implied Probability come in?

Implied Probability is useful when evaluating a bet or checking how likely an outcome is. This is how Predict-O-Vision displays it’s predictions. What’s different about our predictions is that we don’t have a bookies margin - we are giving an unfiltered view of how likely an outcome is in a football match.

Where it gets even more interesting is, when the probability of an outcome is different than what the bookies are giving - it’s here we will want to adjust how we bet. Either the bookies will be giving   



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