Home Field Advantage in Major League Baseball

What is the home field advantage in Major League Baseball?  This isn’t an easy question to answer, but it is an important question to ask when considering betting on baseball.  Because MLB betting doesn’t involve a point spread (there is a runline, but that is a much different story) it’s not as easy for us to establish a baseline for what home field advantage is worth.  Wins, not winning margins are more important when you are betting on the moneyline, so how can we quantify a true home field advantage to increase our winning percentage.

Since 2004, home teams have won 54% of their games during the regular season (meaning road teams win 46% of the time).  It is pretty common knowledge in sports that the home team usually does have some kind of an advantage.  The key here is that we can actually take these numbers and translate them into betting lines.

For all kinds of betting, oddsmakers try to split the action evenly over both sides of a game to minimize their risk, and moneylines are no exception. Using this logic, we can determine a standardized moneyline for home teams versus away teams based on winning expectations.

For example, to consistently make a profit betting -140 favorites, you would need to win about 58% of your wagers (for those who care this is calculated by dividing your risk amount (1.4) by the sum of your risk amount and win amount (1.4 + 1.0 = 2.4)  1.4/2.4=0.583 or 58%).

What we find from our sample is that our 54% home winning percentage translates into a -117 moneyline and our 46% road winning percentage translates into a +117 moneyline, which gives us a home field advantage of about 34 “cents” in terms of the moneyline.

This tells us that we should consider a 34-cent difference in the moneyline between two teams, with the advantage going toward the home team.  Of course, you can and should consider other factors, obviously every home team isn’t listed as a -117 favorite. However, I do think you can use it to your advantage by thinking of this as a baseline when trying to beat the lines this year.

MLB Home-Field Advantage & Win/Loss Records by Team

For the table below, we’ve looked at every regular season game since 2004 for each team.  We have included each team’s home and away margins, as well as the “Home Field” column, which shows the number of runs +/- better each team has been at home vs the road.  While this doesn’t tell you exactly how many more games a team is likely to win at home versus on the road, it does give us a picture of which teams are significantly better at home versus when they play in other stadiums.  Remember, what we are looking for is are teams with a big different between their home/away margins and home/away win percentages.  In many cases this isn’t giving us the “best” teams at home, rather, those teams that are much better at home than on the road, which is what we are looking for.  Teams like the Angels have been pretty good both home and away, so their home field advantage doesn’t register as being as good as a team like the Rockies, who are unsurprisingly much better in their home stadium.