# How bookmakers calculate bets

## How bookmakers set quotes: what are the odds, how to find profitable ones The odds are used to calculate the winnings, but the bookmaker will never be in the red.. Once bookmakers came up with an effective way to calculate the odds, which still works in their favor. Surely every bettor has thought about how operators determine coefficients in their paintings. Where do these numbers come from, how do they put the commission in them and why are they constantly changing?

### What is the coefficient in sports betting

The concept of coefficient is used in various areas of human life. Sports betting is no exception. Here the coefficients are a direct representation of the chances of a particular event in the painting. In other words, the probability of one outcome or another, taking into account the bookmaker’s margin. To make it clear, let’s make a reservation that the margin in sports betting is the bookmaker’s commission embedded in the coefficients.

In our country, the European coefficient is convenient for most bettors. His entry is familiar and understandable to everyone: it is presented in the form of a decimal fraction, usually with two characters after the dot. For example, 1.50, 2.00, 2.43 or 4.58. ### The coefficient determines the possible payout and net profit in case of a successful bet.

The main types of coefficients for sports betting
To date, there are three main types of coefficients, including the European one, which we mentioned earlier. Let’s look at them in more detail.

European coefficient

European quotes are used by all online bookmakers in Europe. How to calculate this coefficient? Multiply the size of your bet by the coefficient, then we will get the amount that the bookmaker will have to pay in case of winning the bet.

According to the European coefficient , the margin is calculated as a percentage using the following formula:

M = (1 / K1 + 1 / K2 + 1 / Kn — 1) x 100, where K1, K2, Kn are the coefficients for the outcomes of one market, n is the number of elections in one market. There are special calculators on the Internet to determine the margin.

As we mentioned earlier, the coefficient entry is represented as a decimal fraction, usually with two digits after the dot. Tip: determine the possible payout by multiplying the bet amount by the coefficient in the bookmaker’s office.

British coefficient

English coefficients remain extremely popular nowadays. And all thanks to British gambling establishments that faithfully honor the traditions of their ancestors.

This type of coefficient is written in the usual fraction. This quote reflects the ratio of the amount of net winnings to the size of the bet. It is most often used in the UK.

The British coefficient is converted to the European one according to the following formula:

Ke = Kb +1, where Ke is the European coefficient and Kb is the British one.

Tip: Determine the potential profit when betting on British fractional coefficients by multiplying the bet amount by the fraction value.

That is, the British coefficient 3/2 is an analogue of the European 2.50. And 5/4 is an analogue of the European 2.25.

American coefficient

American betting odds are most often considered the most rare and difficult to perceive.

The main distinguishing feature of American coefficients is the presence of a «+» or «-» sign before the digital indicator. This sign allows you to determine which team is the favorite. It may seem strange, but the sign of the status of the favorite is precisely the «-» sign.

A plus American coefficient indicates a potential net profit with a bet amount of 100 rubles. The plus American coefficient is converted to the European one according to the following formula:

Ke = Kap / 100 +1, where Ke is the European coefficient, and Kap is the American plus.

The negative American coefficient indicates the amount you need to bet for a potential net profit. The negative American coefficient is converted to the European one by the following formula:

Ke = 100 / (-Kam) +1, where Ke is the European coefficient and Kam is the American minus one. Let’s say the coefficient +125 is an analog of the European 2.25. And -150 is an analog of the European 1.50.

### How the bid coefficient is calculated

Sports betting odds are calculated in three stages. Let’s consider them and give an example of calculating the coefficient.

1. Step 1. Probability. Here bookmakers use the work of analysts who determine the probability of an event. BCS purchase data from special analytical agencies or trust the materials of their employees.
2. Step 2. Calculation of coefficients. At this stage, the results obtained are translated into the corresponding coefficients.
3. Step 3. Adding margin. Bookmakers put the margin in the odds to be in the black at the distance, regardless of the outcome of events.

Let’s say an analytical agency has determined that in a Champions League football match Barcelona — Juventus, the chances of outcomes are as follows:

P1 — 44%

P2 — 38%

X — 18%

If the bookmaker wants to earn 7% of the total amount of finances set by clients on this match, then he divides 7 by 3 (the number of probable outcomes — a victory for the hosts, a draw, a victory for the guests) and gets 2.33%, which he then adds to each chance. As a result , the following chances are obtained:

P1 – 46.33%

P2 – 40.33%

X – 20.33%

Now we convert the percentages into coefficients. To do this, divide 100 by the probability of passing the bet and get:

P1 – 2.15

P2 — 2.47

X – 4.9

Quotes for other positions in the painting are set in the same way.

### Changing the set coefficient: when and why

To deal with this issue, you need to get acquainted with the concept of «fork».

A fork is an opportunity to bet on the outcomes of one market with a guaranteed profit.

Bookmakers pay special attention to the odds of outcomes of sports events in other bookmakers. That is why, in order not to create «forks», the coefficients can change.

There are two main reasons for this.

Changes in the balance of power in the match. Analysts constantly monitor up-to-date information in order to re-evaluate the chances of rivals in case of changes. This may be due to various factors that also need to be taken into account and be able to identify in the process of preparing for the match. Let’s say an injury to a key athlete, a disqualification of a player, or news about a conflict between a coach and football players.
Progruzov. In other words, this is a change in the coefficients with a large number of bets.
Thus, the coefficient in the bookmaker reflects the opinion of analysts and includes margin. Bookmakers react quickly and clearly to changes affecting the outcome, and due to the margin they are in the black at the distance.