How Do Betting Companies Set Odds

1. How Do Betting Companies Set Odds Calculator

It's a simple enough question and one every bookie gets asked. How do we set the odds on Inter not losing at home again or Wigan sneaking victory over title-chasing Arsenal. Well it goes a little like this.

The betting company calculate the probability of each outcome occurring and then subtract the margin. If the real probability is 2/1 (3.0 in decimal, 200 in American) then the bookie will subtract their 5% margin and the real odds given will be 19/10 (2.90, 190).

The key advantage bettors have is that they do not have to wager on every game, but can pick and choose wagering opportunities. The bookmaker however, puts up a number on hundreds of events each and every week. In a typical NFL week, there are 14 to 15 games for you to choose from and there are even multiple betting opportunities on each game. When a point spread is attached to a set of odds it means that for the bet to be successful the team must ‘cover the spread’. This means that the team you are betting on must win or not lose by a predetermined margin of points. For example, the Chargers could have odds of (+4) -110 to win. The betting agencies calculate odds based on the bets placed. They typically keep around 5% and pay the rest out. So a lot of money placed on a particular outcome will reduce the payout for that outcome.

There are a team of people employed by any bookmaker, usually referred to as Traders, Risk Analysts or Odds Compilers. Their job is to produce odds that closely represent the chance of an occurrence.

It’s a tough job to account for all the variables in any event. If you take the chance of Manchester United winning at home for example the trader has to account for the form of the teams, injuries to key players, influence of the crowd, the referee and many others.

In addition to the chances of a team winning, they have to account for the money that is likely to be placed. In the Manchester United example, most people would back the Red Devils to to win at Old Trafford and therefore the odds will be shorter than perhaps the precise chances of victory.

Also like any other business a bookmaker has to make money so the Trader will add a small percentage to a ‘book’ in order to generate this profit. In a match between two evenly matched teams on a neutral ground the odds might look something like the following:

This adds to approximately 100% and trading books like this, the bookmaker should break even over a period of time. So what they have to do is skew the odds slightly in their favour:

Now the bookmaker has a 9.4% profit margin and should make a profit over time although to the punter of course it’s all about making a profit on the game itself! A bookmaker will trade a market at anywhere between 101 and 120% profit depending on the market and competitor activity.

That means that in a perfect world (which doesn’t exist) the bookmaker should make between £1 and £20 for every £100 that are gambled on the market. What happens in reality however is that most money is gambled on the favourites and it’s when the favourites fail to win, that the bookmakers make their money.

David Mole is Goal.com's Betting and Odds Expert. He has previously worked for Betfred, Victor Chandler, William Hill and Totesport.

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Welcome to the Sports Betting Odds section of The Sports Geek. If you are new to sports betting and don’t understand how to read betting odds (+150, -110, +2200, etc) we will lay it all out for you and help you learn how the betting odds work.

Sports Betting Odds Explained

Many people don’t know how to read or calculate sports betting odds, so below we have done our best on explaining how betting odds work. The most common type of sports betting odds used in North America are the American style odds which we explain below.

American Style Sports Betting Odds

Most online sportsbooks will list their odds in what is called “American Odds”. There are a couple different versions of sports betting odds, but these American Odds are the most common odds used. Reading and understanding sports betting odds can bet a little confusing to beginners, so we have provided an example below using two NFL football teams:

American Odds

• Matchup Odds
• New England Patriots +120
• Pittsburgh Steelers -140

The number shown in the bracket represents the odds. The American Odds have two components to them, the first being the positive or negative sign, and the second being the number that follows the sign.

The sign in front of the number indicates whether placing a wager on that outcome will pay out more money then you have wagered or less money then you have wagered. If the odd is negative (-) it means that outcome is more likely to happen and placing a bet on that outcome would payout less than the amount you wagered, while a positive (+) odd shows that the outcome is less likely to happen and it would pay out more than the amount you wagered.

The next step is figuring out exactly how much the bet pays out, which is where the numbers in the odds come into play.

A listed odd with a – sign in front of it, such as the -140 in our example above, shows us how much money you would need to wager in order to win $100. So using the -140, this would show us that you would need to bet $140 in order to win $100 in profits. You can easily substitute the $100 bet for a $10 bet by moving the decimal place over one spot, showing us that you would need to wager $14 in order to win $10 in profits.

Examples:

A listed odd with a + sign in front of it, such as the +120 in our example above, shows us how much money you would win on a $100 bet. Using the +120 odds, it shows us that a $100 bet on that outcome would pay out $120 in profits. Again this can easily be converted into smaller or larger size bets. A $10 bet on +120 odds would pay out $12 in profits.

Examples:

Below is an example of NFL betting odds taken from an online betting site.

In this example you can see Los Angeles is listed at +130 ($100 bet pays $130 plus of course your original wager back) and New England is listed at -150 ($150 bet pays $100).

The great thing about betting online is that the online sportsbooks will do the calculations for you before you place your bet. You can click on the outcome or team you would like to bet on, and then input the amount you wish to wager and it will show you your potential pay out before you confirm your bet.

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Decimal Style Sports Betting Odds

Decimal style odds are used mostly in Europe, and are pretty easy to understand. To calculate the decimal style odds all you will need to do is simply multiply the amount you wish to wager by the decimal odds shown and you will get your payout. For example it may look something like this:

If you wanted to place a $10 wager on the USA at 2.40 you would simply need to multiply your $10 wager by the 2.40 odds (10 x 2.40) to find out that the payout is $24. It is important to realize that with decimal style odds it includes the amount you wagered, so to find out profits you would need to subtract your wager ($24 – $10) to find out your potential payout is $14 in profits.

If you wanted to place a $10 wager on Brazil you would again just multiply $10 x 1.55 to find out that you would win $15.50 total or $5.50 in profits.

How Do Betting Companies Set Odds Calculator

Decimal style betting odds are very simple to understand, but you won’t see them displayed in many North American sportsbooks. With that said, most online betting sites will allow you to chose the style of betting odds you want displayed, with American odds set as the default.