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Betting Odds Calculator

How to Calculate Betting Odds

Betting Odds Calculator
One of the big aspects of understanding the odds which you see at a bookmaker is knowing what they actually mean in terms of probability. The odds that are presented, are calculated by the bookmaker in relation to what the bookmaker thinks the chances of a certain outcome of a sporting event happening is.

For example, a 2018 UEFA Champions League match between Liverpool and PSG read Liverpool 6/5, Draw 13/5 and PSG 2/1. With those odds, you can easily calculate the amount of return that you would get back from placing a bet on either of those outcomes. But what are the implied chances of each of those outcomes happening? It is important to know because this also relates to the risk of your bet.

So let's take a look at just how to convert odds to probability (percentages)
Odds / Probability Converter

Convert Fractional odds to probability

The most common form of odds are going to be decimal odds in the UK and here is how to convert decimal odds to probability. These are clear odds to read and for example the 6/5 odds on Liverpool from the example above means that for every 5 units you put on, you will receive 6 back as a profit.

To convert Fractional odds to probability there is a simple calculation of Denominator divided by (Denominator + Enumerator) multiplied by 100.

For our 6/5 odds that is 5 / (6 + 5)
Which calculates to 5 / 11
5 / 11 equals 0.45
0.45 multiplied by 100 = 45%

So the bookmaker believes that Liverpool has a 45% implied chance of winning the game.

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Convert decimal odds to probability

Many punters like reading odds presented in the decimal format because it simply tells you what you are going to get returned to you from a bet, including the stake. It is a little bit less cumbersome in converting decimal odds to probability as well. The decimal odds on our Liverpool v PSG game are Liverpool 2.20, draw 3.60 and PSG 3.10

It is a simple formula of 1 divided by decimal odds multiplied by 100. Let's stick with the Liverpool 2.20 odds.

1 / 2.20 = 0.45 0.45 multiplied by 100 = 45%

Converting decimal odds to percentages

So it is all important stuff to know because you want to know the real risk in terms of probability of what your money is going down on. Remember that when you are converting odds to percentages then there is always a bookmaker percentage worked into the deal.

What we mean by that as if you were to calculate odds to percentages on each of the three outcomes for the Liverpool v PSG game we are using as an example, it wouldn't total 100%. It would be more. Most totals like this on the outcome of a sports event will calculate out to around between 103% and 105% which is the margin that the bookmakers run at for their profits.

Converting probability to odds

There is also the scenario of when you may need to convert a probability number to odds. This could be super useful when looking for Value Bets, where you assess your own chances of an outcome of a match. Once you have gotten the odds from your percentage prediction, then you can go hunt around for those odds which represent the best value for you.

Calculate probability from odds

Fortunately for ease and efficiency, you can find our conversion calculator which will do all of the work for you. You don't have to break out the pencil and paper and start figuring things out, you can calculate probability from odds quickly by just plugging in the numbers. Just choose between the decimal or fractional odds input, plug in the numbers and away you go. You can also convert probability into odds in the calculator too.