What Does BB Mean in Baseball?
Quick answer
BB is the scorebook abbreviation for a base on balls, better known as a walk: the batter goes to first base after four pitches outside the strike zone.
In this article
BB stands for "base on balls," the official name for a walk. When a pitcher throws four pitches outside the strike zone that the batter doesn't swing at, the batter is awarded first base. In a box score or on a stats page, the walks column is labeled BB.
How a walk works
- A ball is a pitch outside the strike zone that the batter doesn't swing at.
- Four balls in one plate appearance and the batter takes first base.
- Runners who are forced (for example a runner on first) move up one base. Other runners only advance if forced.
- A walk with the bases loaded forces in a run.
BB in batting stats
| Stat | What BB does to it |
|---|---|
| Batting average | Nothing. A walk isn't an at-bat |
| On-base percentage (OBP) | Raises it. Walks count as times on base |
| Slugging percentage | Nothing. Walks aren't hits |
| Walk rate (BB%) | Walks divided by plate appearances |
Hitters with a good eye draw lots of walks, which is why on-base percentage is such a useful stat. A walk isn't as good as a hit with runners on, but it's far better than an out.
BB in pitching stats
For pitchers, walks are a sign of control problems:
- BB: total walks allowed
- BB/9: walks per nine innings (lower is better)
- K/BB: strikeouts per walk (higher is better)
- WHIP: walks plus hits per inning pitched
Intentional walks (IBB)
An intentional walk is when the defense chooses to put the batter on first, usually to face a weaker hitter or set up a force or double play. Since 2017, an MLB manager can simply signal for it instead of the pitcher throwing four wide pitches. It's recorded as IBB, and it also counts in BB totals.
Related terms
- Hit by pitch (HBP): also puts the batter on first, but is not a walk
- Full count: three balls and two strikes, one ball away from a walk
- 3-0 count: three balls, no strikes
See more abbreviations and slang in baseball terms explained.
Frequently asked questions
What does BB stand for in baseball?
BB stands for base on balls, the official name for a walk. The batter goes to first base after the pitcher throws four balls.
Does a walk count as an at-bat?
No. A walk is a plate appearance but not an at-bat, so it does not lower a hitter's batting average. It does raise on-base percentage.
What is IBB in baseball?
IBB means intentional base on balls, an intentional walk. Since 2017 MLB teams can signal for one without throwing four pitches.
What does BB/9 mean?
BB/9 is walks per nine innings, a pitching stat that measures control. Lower is better.
