Run lines
The run line is baseball's point spread. The number is nearly always 1.5 runs, so instead of moving the runs the book moves the price, and the bet becomes a question of whether the favorite wins by two or more. It is a different bet from the moneyline, not a cheaper way into the same one.
A spread that doesn't move
In football the book sets the spread wherever it splits the betting, and it can be 3, 7 or 13.5. Baseball doesn't score enough for that to work. Most games are decided by a handful of runs, so at 3.5 runs nearly every underdog would be a heavy favorite to cover. The book fixes the spread at 1.5 instead and lets the price carry the difference between the two teams. (Hockey does the same thing and calls it the puck line; the spreads page covers both from the football end.)
So a baseball point spread looks like this, with the moneyline next to it for comparison:
| Bet | Price | To win $100 | Break-even |
|---|---|---|---|
| Favorite moneyline | -170 | risk $170 | 62.96% |
| Favorite -1.5 | +130 | risk $76.92 | 43.48% |
| Underdog +1.5 | -150 | risk $150 | 60.00% |
| Underdog moneyline | +155 | risk $64.52 | 39.22% |
The favorite at -1.5 has to win by two runs or more. The underdog at +1.5 wins the bet if it wins the game or loses by exactly one.
Grading it
Take three results. The favorite wins 4 to 3: the moneyline on the favorite wins, but 4 minus 1.5 is 2.5, which loses to 3, so the favorite at -1.5 loses and the underdog at +1.5 cashes. The favorite wins 5 to 3: 5 minus 1.5 is 3.5, it covers, and everything on the favorite wins. The underdog wins 3 to 2: the underdog wins on both lines, and the favorite loses on both.
There is no push, because the half run makes one impossible. That is the point of the half.
What the two prices tell you
Read the table across and the book has told you what it thinks of one-run games. The favorite's moneyline says it wins about 63 percent of the time. Its run line says it wins by two or more about 43 percent of the time. The gap, near 20 percentage points, is the share of games the prices expect to end as a one-run win for the favorite. Those figures carry the book's margin, so treat them as rough, but the shape is right: one game in five, in this example, is a win on the moneyline and a loss on the run line.
That is why I never liked hearing a player say he took the run line because the favorite was "too expensive". The price at -170 wasn't too expensive. It was the price of the favorite winning. At +130 he is betting on something else, something that happens less often, and the book has priced that too.
The home favorite
The run line treats the two teams differently, and most bettors never notice. If the home team is ahead after the top of the ninth, it doesn't bat again. And if it wins in its last at-bat, the game ends the moment the winning run scores, so unless the winning hit is a home run, a walk-off win is by exactly one run. A home favorite gets fewer chances to stretch a lead than a road favorite does, which still bats in the top of the ninth, and of every extra inning, whatever the score.
Books know it, and a home favorite at -1.5 usually comes at a better price than a road favorite of the same strength. Whether it is better enough is the handicapping.
Reverse and alternate run lines
Most books will also deal the line the other way round: the favorite at +1.5, at a heavy price, and the underdog at -1.5, at a long one. Say the favorite +1.5 is -300 and the underdog -1.5 is +220. Laying -300 means risking $300 to win $100, and you need to win 75 percent of the time just to break even. One two-run loss wipes out three wins. I wouldn't lay that to protect a favorite I already liked on the moneyline.
The underdog at -1.5 needs the worse team to win by two, which is a long shot priced as one. Alternate lines at 2.5 runs and beyond work the same way, each half run further from the standard number priced further out.
When the bet counts
Most books need the full game for a run line bet to have action: nine innings, or eight and a half if the home team is ahead. A game called for rain after six innings can stand on the moneyline and be void on the run line. Extra innings count. Most books also tie the bet to the listed starting pitchers, as they do on the moneyline. The house rules page has the details, and how to bet on baseball covers the rest of the sport's menu.
Where I'd use it
I'd bet a favorite at -1.5 when I thought the gap between the starting pitchers was wide and the favorite's bullpen wouldn't give a lead back, which is a reason to expect a margin, not just a win. I'd look at the underdog +1.5 when I thought a game would be close and low scoring, but I'd always set it against the underdog's moneyline first. In the example, the extra run costs you the difference between +155 and -150. That is a lot to pay for one run.
Shop it as you would any price. A run line at +130 at one book and +120 at another is the same bet, and the difference adds up over a season of 162 games a team. Size each one against your bankroll, because a plus price on a favorite still loses more often than it wins.