How Do Bookmakers Determine Odds

Different sorts of gambling are available to us now and it has never been easier to enter this world than now! There are numerous ways of betting nowadays and thousands of possibilities to earn money. However, ones without whom nothing would be possible are bookmakers.

Betting Shop

A bookmaker is someone who promotes gambling, most typically on athletic events, by determining odds, taking and making bets, and paying out profits to others. He sets the odds so that he profits regardless of who wins the wager. Odds are a bookmaker’s assessment of the probability of a given event. He sets the odds based on his judgment of who has a better likelihood of winning. A bookmaker’s ultimate goal is to set odds that are favorable enough to generate him a profit every time, regardless of who wins the bet.

In this article, we will go under the surface of odds and how bookmakers truly determine them, as well as the calculations that lie behind them.

1. The commission

The process of determining odds begins with selecting the commission percentage that the bookmaker wants to earn on each wager on each event.


The betting house will then estimate the likelihood of outcomes and deduct the commission margin. For example, if a bookie’s commission is set at 10% on an odd of 2.00, the final odd will be subtracted by that commission – in this case, 1.80. The method of estimating the chances includes a variety of parameters such as statistics, the form of the team or player, head-to-head history, and the bookmaker’s judgment on what may and may not happen.

2. Outcome factors

One of the crucial parameters when a bookmaker determines the odds is his rough assumption of how many bets there will be on one outcome. Therefore, the more bets on one outcome, the bigger his margins, and finally, the bigger the odds. Secondly, they take every single possible parameter into account and they are, for example, the popularity of an individual or a team, and the real probability of one side winning the tie.


Either way, no matter the outcome of a bet, the bookmaker will be happy as long as his commission is big bringing him the money. The odds size can help evaluate if a risk is worthwhile to follow or not.

3. Bookmaker’s mistakes

As every other human, bookmakers can make mistakes, too! Rarely, but it happens. They don’t really like the favorites thing so, to make a profit, they will determine the bigger odds possible in order to mentally affect the people to make a bet on the other team which has a smaller chance of winning. As bookmakers can go wrong in determining the odds, they can underestimate the team they gave a small or no chance to win. When that team wins, and with the odds being drastically different from those of the favorites, they need to cash out big amounts of money.

Financial Investment

4. The bookmakers are winning

There are a few of them who made a fortune gambling and the only winner here are the bookmakers and the house. The payout to the individual is always less than what the house and bookmaker have earned in the process. This is called profit margin and, as we mentioned above, the odds are decided after every side fits in their profit demands.

As a result, the bookmaker must be accurate in judging the true likelihood of each outcome in order to meet his profit demands. When everything is done perfectly, they profit regardless of the result of an event.


When you add up odds probability numbers that need to be 100%, every percent more represents the profit margin of the bookmaker. Let’s say the odds betting house offered are as follows: Team One has a probability of winning the match by 82%, and Team Two has only 23%. Here we get the sum of 105%; we can conclude the bookmaker’s profit margin here is 5%!

5. Winning Formula

In this industry, ordinary players are statistically those with losses. The bigger the odds, the less money you can potentially win. For winning a bigger amount of cash, you need to play more, and the more you play, the probability of you losing the money is sky-high which leads us to the conclusion that you will sooner or later end up with huge losses even if you win now and then.



Gambling on sports events can be profitable if you smartly choose which events you can put your money on. The odds never reflect the true probability of an event’s result as you always end up winning less money than you should if the odds had reflected the true probabilities and that’s completely for one reason only – the bookmaker’s profit margin!

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