MLB run line calculator
The run line is baseball's spread, nearly always 1.5 runs. Enter how likely a team is to win and the calculator shows how often teams like that won by two or more, with fair odds for both sides of any run line.
History covers 26.1% to 73.2%.
Team's run line: -1.5Negative gives runs (favourite), positive receives them. Steps of 0.25.
Team -1.5 runs
42.8%
covers
- Push
- 0.0%
- Loses
- 57.2%
- Fair odds
- +134 · 2.34
- Break-even
- 42.8%
Opponent +1.5 runs
57.2%
covers
- Push
- 0.0%
- Loses
- 42.8%
- Fair odds
- -134 · 1.75
- Break-even
- 57.2%
Lines either side
| Team line | Covers | Push / half | Loses | Fair odds |
|---|---|---|---|---|
| -2.5 | 32.6% | 0.0% | 67.4% | +207 · 3.07 |
| -2.25 | 32.6% | 0.0% / 10.2% | 57.2% | +191 · 2.91 |
| -2 | 32.6% | 10.2% | 57.2% | +175 · 2.75 |
| -1.75 | 32.6% | 10.2% / 0.0% | 57.2% | +152 · 2.52 |
| -1.5 | 42.8% | 0.0% | 57.2% | +134 · 2.34 |
| -1.25 | 42.8% | 0.0% / 17.2% | 40.0% | +114 · 2.14 |
| -1 | 42.8% | 17.2% | 40.0% | -107 · 1.94 |
| -0.75 | 42.8% | 17.2% / 0.0% | 40.0% | -128 · 1.78 |
| -0.5 | 60.0% | 0.0% | 40.0% | -150 · 1.67 |
Fair odds have no bookmaker margin: a price longer than them is value on these numbers. Based on 36,531 games from 2010 to 2026; this probability is read from the 6,085 team-games closest to it.
MLB run line cover rates by win probability
How often a team covered each run line, by how often teams like it won. 36,531 games, 2010–2026.
| Win prob. | -2.5 | -1.5 | +1.5 | +2.5 |
|---|---|---|---|---|
| 30% | 15.4% | 20.8% | 47.5% | 58.5% |
| 35% | 17.0% | 24.3% | 51.8% | 63.0% |
| 40% | 19.2% | 27.7% | 57.4% | 67.7% |
| 45% | 24.1% | 32.7% | 60.4% | 70.4% |
| 50% | 26.4% | 35.5% | 64.4% | 73.6% |
| 55% | 29.9% | 39.6% | 67.4% | 75.9% |
| 60% | 32.6% | 42.8% | 72.4% | 80.8% |
| 65% | 37.3% | 48.2% | 75.6% | 82.8% |
| 70% | 41.0% | 52.6% | 79.1% | 84.6% |
What a run line says about win probability
The win probability at which each line is a fair bet, pushes aside, and the moneyline that probability is worth with no margin.
| Favourite's line | Win probability | Fair moneyline | Underdog |
|---|---|---|---|
| -1.5 | 66.9% | -202 | +202 |
| -1 | 58.4% | -141 | +141 |
| -0.5 | 50.0% | -100 | +100 |
Common questions
- What win probability does a 1.5-run favourite have in MLB?
- About 66.9%. Across 36,531 MLB games from 2010 to 2026, teams that won 66.9% of the time covered -1.5 exactly as often as they failed to, pushes aside, so -1.5 is a fair line for them. As a moneyline with no margin that is -202.
- How often does a 60% MLB favourite cover -1.5?
- 42.8% of the time in the history behind this calculator, which makes the fair price on that side 2.34 in decimal odds (+134).
- How does the calculator turn a win probability into handicap odds?
- It uses real results, not a formula. Every MLB game since 2010 is seen from both teams, grouped by its pre-game chance of winning (the betting market's, or AccuScore's projection where no price was recorded), and each group is labelled by how often its teams actually won. The probability you enter is matched to the groups that won that often, and their final margins decide how often each run line was covered.
- What is a quarter line?
- A line ending in .25 or .75 is two bets in one: half the stake on each line either side. -0.75 is half on -0.5 and half on -1, so a one-run win wins the first half and pushes the second. That is why quarter lines can win or lose half the stake.
- Why does the calculator stop at 26.1% and 73.2%?
- Those are the most lopsided MLB games history has enough of. Beyond them there are too few results to say how often a line is covered, and the calculator does not guess.