How Many MLB Games Are Decided by One Run? 26 Seasons of Data
Twenty-six seasons of regular-season results show how often MLB games come down to a single run, how stable that is, and why the home side owns the tight finishes.
Anyone who bets baseball run lines eventually asks the same thing: how often does a game land on the one-run margin that decides whether a favourite covers? I went through 61,241 regular-season games of 9 or more innings from 2000 to 2025 to find out.
The headline answer is 28.3% of games were decided by exactly one run, and that figure has barely moved in 26 seasons. The more useful finding for a bettor sits underneath it. Home teams win those close games far more often than they win anything else, and a large slice of that comes from the structure of the ninth inning itself.
One run is by far the most common final margin
This chart shows every final margin as a share of all games. The one-run bar towers over the rest, with 18.0% of games settled by two runs and the shares tapering steadily from there. Blowouts of 10 or more account for just 3.7%.
This is the base rate I keep in my head before I look at anything on my MLB betting tips page. If you lay the run on a favourite, you are betting against the single most likely outcome in the sport, which is the favourite winning by exactly one.
View the data: final margin in mlb games
| Share of 9+ inning games, 2000-2025 | |
|---|---|
| 1 run | 28.3% |
| 2 runs | 18.0% |
| 3 runs | 14.3% |
| 4 runs | 11.6% |
| 5 runs | 8.4% |
| 6 runs | 6.1% |
| 7 runs | 4.4% |
| 8 runs | 3.0% |
| 9 runs | 2.1% |
| 10+ runs | 3.7% |
The steep drop after one run is why run-line prices behave so differently from moneyline prices. The step from winning to covering removes the fattest part of the distribution.
The one-run share holds steady across 26 seasons
Season by season, the one-run share ranged from a low of 26.3% in 2003 to a high of 31.0% in 2011, and it finished at 29.4% in 2025. The line wobbles, but it never escapes a fairly narrow band.
The overall estimate carries a 95% range of ยฑ0.4, so the long-run figure is solid. Individual seasons drift with the run environment, bullpen usage and plenty of noise, which is exactly why I would not chase a single year's reading.
View the data: one-run games by season
| Decided by one run | |
|---|---|
| 2000 | 28.8% |
| 2001 | 26.9% |
| 2002 | 27.9% |
| 2003 | 26.3% |
| 2004 | 26.4% |
| 2005 | 29.6% |
| 2006 | 27.9% |
| 2007 | 28.0% |
| 2008 | 28.0% |
| 2009 | 27.1% |
| 2010 | 30.2% |
| 2011 | 31.0% |
| 2012 | 28.7% |
| 2013 | 31.0% |
| 2014 | 30.5% |
| 2015 | 29.1% |
| 2016 | 28.3% |
| 2017 | 26.6% |
| 2018 | 27.5% |
| 2019 | 26.7% |
| 2020 | 27.3% |
| 2021 | 28.0% |
| 2022 | 28.9% |
| 2023 | 27.7% |
| 2024 | 27.8% |
| 2025 | 29.4% |
What I take from this is patience. A season that runs hot on close games is not a new era, and a quiet one does not mean the tight finish has gone away.
Margin mix barely shifts between the three eras
Grouping seasons into eras smooths out the year-to-year noise. One-run games made up 27.7% in 2000-09, 29.0% in 2010-19 and 28.3% in 2020-25. The other end of the scale is just as stable: games decided by 5 or more runs were 28.4% in the first decade and 28.1% in the most recent stretch.
The middle decade shows a slightly tighter game overall, with fewer lopsided results, but the differences are small. For my purposes, the shape of a baseball scoreline is one of the more dependable things in the sport.
View the data: margin mix by era
| 1 run | 2 runs | 3-4 runs | 5+ runs | |
|---|---|---|---|---|
| 2000-09 | 27.7% | 17.9% | 26.0% | 28.4% |
| 2010-19 | 29.0% | 18.4% | 25.8% | 26.8% |
| 2020-25 | 28.3% | 17.7% | 26.0% | 28.1% |
One honest caveat belongs here. These are league-wide base rates, and they hide real team-level differences in bullpens and run environments, while the 2020 season had only 60 games per team. A strong late-inning relief corps or a hitter-friendly park can move a specific matchup well away from these averages.
Home teams win close games far more than blowouts
This table is where the study earns its keep. Home teams won 60.7% of one-run games, against 51.0% of games decided by two or more. In nine-inning one-run games, covering 13,593 contests, the home side still won 59.7%, and in extra-inning one-run games it rose to 64.3%.
The mechanism is structural. The home team bats last, so when it takes the lead late it stops the moment it is ahead. In fact, 45.0% of home one-run wins were walk-offs, which naturally caps the margin at exactly one.
| Games | Count | Share of all | Home win % |
|---|---|---|---|
| One-run, 9 innings | 13,593 | 22.2% | 59.7% |
| One-run, extra innings | 3,752 | 6.1% | 64.3% |
| All one-run games | 17,345 | 28.3% | 60.7% |
| Decided by 2+ runs | 43,896 | 71.7% | 51.0% |
Extra innings amplify this. 71.4% of extra-inning games ended by one run, 72.1% from 2000 to 2019 and 68.8% since the 2020 runner-on-second rule, and one-run extra-inning games made up 21.6% of all one-run games. For a home favourite on the run line, that walk-off ceiling is a quiet but persistent headwind.
What I take from this
- Respect the base rate. With 28.3% of games decided by one run, the single most likely outcome for any favourite is a narrow win that fails to cover the run line.
- Home favourites cap themselves. Because 45.0% of home one-run wins were walk-offs, home sides often cannot win by more than one, which matters every time I consider laying the run with them.
- Trust eras, not seasons. The share has sat between 26.3% and 31.0% for 26 seasons, so I treat any single hot or cold year as noise rather than a shift.
Questions from readers
What percentage of MLB games are decided by one run?
Across 61,241 regular-season games from 2000 to 2025, 28.3% were decided by exactly one run. In 2025 the figure was 29.4%.
Do home teams win more one-run games in MLB?
Yes. Home teams won 60.7% of one-run games compared with 51.0% of games decided by two or more runs, largely because they bat last.
How often do extra-inning MLB games end by one run?
71.4% of extra-inning games ended with a one-run margin. Since the 2020 runner-on-second rule the figure has been 68.8%, against 72.1% from 2000 to 2019.
I'm Olivia Reardon, based in Auckland, and I write the MLB predictions at htftpredictions.com โ a sport where pitching matchups and patience matter most.
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