The baseball moneyline
By now you’re familiar with the moneyline. A moneyline bet is a bet on a team to win the game. It doesn’t matter by how much; it doesn’t matter if it’s in 9 innings or 19 innings.
To split the betting action between teams of differing quality, oddsmakers have two choices:
They can handicap one team by including a point spread. Betting on either side will be close to an even-money 11/10 bet, but the final score is adjusted by a certain number of points to determine the winner of the bet.
The alternative is the moneyline, where the final score of the game indicates the winner, with no point or run adjustments, but the payout schedules are different depending on whether you bet on the favorite or the underdog.
There are different explanations for why baseball doesn’t operate with a point spread. One theory is that margin of victory in a baseball game has less to do with the quality difference between the two teams. Another is that overall variability of the game makes it more difficult to attach a spread to. Historians point out that after horse racing, baseball is the original bettors’ sport, and by the time the point spread was invented in the 1940s, there was enough accumulated knowledge and tradition in offering odds on baseball bets that the points spread simply wasn’t necessary.
Either way, a moneyline is a moneyline. Baseball moneylines are no different from any other moneyline: You need the team you bet on to win the game if you want your bet to pay off.
Moneyline encoding
The moneyline of a baseball game comes with several key pieces of information. Let’s consider a baseball game where the home team is listed at –110 and the road team is listed at +100:
The home team is a slight favorite. The break-even winning percentage for a bet placed at –110 odds, as you know by now, is 52.4 percent. (To calculate breakeven rate on a negative (favorite) moneyline, divide the line by itself less 100 (–110/–210).
The break-even percentage on the underdog (+100) is 50 percent.
The bookmaker’s vigorish, or theoretical hold, is about 2.3 percent. A moneyline by itself does not tell you how much vig is being charged by the bookmaker; you need both the favorite and the underdog moneylines to determine what the vig is.
There are no ties in baseball (except in the occasional All-Star game). Your moneyline bet is on the final result of the game, including extra innings (if they are necessary).
Win-loss record perils
If you’re a moneyline bettor in baseball, you can’t judge your success by looking at your win/loss percentage. If you bet on every baseball team with a –170 moneyline in the 2019 season, you would have won 62 percent of your bets! That sounds like a lot of winning, right? Let’s do a quick calculation to see if you would have broken even:
Since we’re looking at bets in the past, we know the actual winning percentage of the bets (62 percent). What we’re interested in is the break-even winning percentage of bets at a –170 moneyline. If those 2019 bets won at a higher rate than the break-even winning percentage, it means they would have been profitable. If the actual winning percentage is below the break-even rate, they would have lost money.
For a favorite, the break-even winning percentage is the moneyline (–170) over itself minus 100 (–270). Here’s the calculation:
–170/–270 = 62.9 percent
So you have to win 62.9 percent of –170 bets to make a profit. That should make sense to you since every time you lose a –170 bet, you’re losing $170 (or $17 or $1.70), and every time you win that bet, you only win $100 (or $10 or $1, respectively). Winning less than 62.9 percent means you’re losing money, and that’s just what would have happened in 2019 had you bet on every single –170 favorite. It might feel strange to win 62 percent of your bets and lose money, but since 62 is less than 62.9, that sad fate is what would have befallen you.
The flip side of that is that if you’re an underdog bettor, it feels strange to win less than 50 percent of your games and be profitable, but that’s what happens sometimes. In 2018, if you had bet on the Marlins every time they were +250 or greater underdogs, you would have won 2 and lost 5. But because those occasional payoffs are worth so much more, that 2–5 record would have also netted you a +14.3-percent ROI.
Point spread bettors can generally tally up wins and losses and judge whether they’ve been successful or not. And the point spread gives you an explicit message, “The betting market thinks Team A is 6 points better than Team B.”
There are no such signposts when you’re a moneyline bettor. When wins and losses become less meaningful, you are forced to think in terms of win probability, ROI, and returns. But don’t be afraid: With a little experience, you’ll learn to calculate in your head. When you see a moneyline on a baseball game, you’ll be able to do a quick mental calculation on the implied odds and decide whether they match your expectation on the outcome.