# How to Calculate the Expected Value of a Betting Line

In baseball, the betting line is the amount of money a bookmaker is willing to risk on a particular team winning or losing a game. For example, if a bookmaker is betting \$10 on the Reds to win, then they are actually expecting the Red win the game by at least 10 points. If the actual score of the game is 6-0, then the bookie taking the \$10 wager will lose that money but keep the bet alive for the next game. If a bookmaker is betting against the Reds, meaning they are expecting the Reds to lose, then they would set the line at, for example, -290 for a \$10 wager.

The point of a betting line is to give the bookmaker the expectation of what the score of the game will be so that they know how much they have to gain or lose from a particular wager. If you are new to betting or simply looking for a way to better understand the concepts behind it then this article is for you.

## The Basics Of Calculating The Expected Value Of A Betting Line

There are several ways to calculate the expected value of a betting line, but the one we will use here is based on simple probability theory. Let us examine how this works in practice by using a few examples.

• If a bookmaker sets the betting line for a game at +300/+400, then they are expecting the home team to win by 3 or more points.
• If they set the line at +200/+300, then they are expecting the home team to win by 2 or more points.
• If they set the line at +100/+200, then they are expecting the home team to win by 1 or more point.
• If they set the line at -300/-400, then they are expecting the away team to win by 3 or more points.
• If they set the line at -200/-300, then they are expecting the away team to win by 2 or more points.
• If they set the line at -100/-200, then they are expecting the away team to win by 1 or more point.

What if there is no line set for a particular game? In that case, you have to calculate the expected value based on previous games. For example, if the home team is 5-1 in their last six games and they play the same team in a single game this week, then we can use that information to calculate the home team’s expected score for this week’s game.

To do this, we will use a little bit of advanced math introduced in middle school (if you haven’t taken algebra yet, it’s time to learn it!). Consider a group of six consecutive games. For the first game, set the line at +300/+400. For the second game, set the line at +200/+300. For the third game, set the line at +100/+200. For the fourth game, set the line at +50/+100. For the fifth game, set the line at 0/+50. For the sixth and last game, set the line at -300/-400. Now, we just have to add up all the points scored in each game to get the home team’s expected score for this week’s game.

Here is the formula for our example:

{{((5*4)+1)+((4*3)+1)+((3*2)+1)+((2*1)+1)+((1*0)+1)+(-3)}}

10+9+8+7+6+5 = 49

You can do the same thing for the away team to determine their expected score for this week’s game.

Once you have the home team’s and the away team’s expected scores for the game, you can determine the actual value of the betting line by using this handy little bit of formula:

{{((home team score)-(away team score))/2+((home team score)-(away team score))/2}}

-7+7=4

If we were betting on the Reds to win this week’s game, then we would put \$4 on the Reds because the home team’s expected score for the game is 4 and the away team’s expected score is 7. If the Reds win the game, we win \$7. If the Reds lose the game, then we lose \$4. Simple enough!

Keep in mind that this is just one method of calculating the expected value of a betting line and there are many others. Before relying on this particular method, you should try a few different methods and see which one gives you the best results. Also, sometimes the actual score of a game can be surprising. For example, if the home team scores a lot in the first half, but then scores a few less points in the second half, then that would actually make the home team’s expected score higher than the final score would suggest. This is just another example of why it is important to do your research before relying on one method.

## Expected Value Of A Betting Line: General Guidelines

Once you have calculated the expected value of a betting line, you can begin to use it more effectively by following a few guidelines. First, make sure that your expectations are reasonable. If you have ever watched a lot of professional sports, then you know how games are often closer than you would expect. This means that a team with a 45 point lead at halftime may unexpectedly end up losing by 4 points. If you are setting a betting line for a game that is unlikely to end in a blowout, then take that into consideration and adjust your expectations accordingly.

Another important thing to keep in mind is that the line is never going to be 100% accurate because there is always some degree of uncertainty associated with any type of wagering. However, you can use the line to get a good idea of what the spread is and how much money you are likely to win or lose by making a particular wager. This is why you should never place a wager on a sporting event you are not thoroughly familiar with. You can Google search the odds for various sports or browse the Internet for information about upcoming games. If you want to get more accurate results, then you should look for a betting calculator and use that instead.

You should also look for betting lines for other important sports games that you are interested in following. Doing this will give you a good idea of what other people are expecting and how much winning or losing money you can expect. The more you know, the easier it will be to utilize betting lines correctly.

There are three basic guidelines that we would like to emphasize here:

• Never bet on a game you are unfamiliar with. The less you know, the more you are likely to lose.
• Never bet on a game when you can’t afford to lose. The same amount you have at stake is a little bit of money you cannot afford to lose.
• For the games you are familiar with, use the tools that are available to you. There are online betting calculators that can give you a good idea of how much you will win or lose based on the line you choose. Not only that, but you can also enter in the amount you are willing to wager and the bookmaker’s odds. That way, you can verify what you are getting before placing that wager.