What Does BB Mean in Baseball? Definition & Stats

By Emma Wilson · September 4, 2027

In baseball, 'BB' stands for 'base on balls,' commonly known as a walk. It occurs when a pitcher throws four pitches outside the strike zone, and the batter doesn't swing at any of them, allowing the batter to advance to first base.

What Does BB Mean in Baseball?

The term BB, short for base on balls, is an official statistic in baseball that records when a batter is awarded first base after receiving four pitches outside the strike zone. This event is more commonly referred to as a walk. A walk does not count as a hit or an at-bat, but it does count as a plate appearance and can significantly impact game strategy.

Why Is a Walk Important?

Preserves the batter's on-base percentage without using a hit
Can force in a run during a bases-loaded situation (called an IBB or walk-off walk)
Disrupts the pitcher's rhythm and pitch count
Is a key component of patient offensive approaches

Types of Walks in Baseball

Not all walks are the same. There are two primary types:

Unintentional Walk

This is the standard walk, where the pitcher loses control or the batter demonstrates discipline by refraining from swinging at bad pitches.

Intentional Walk (IBB)

An intentional walk occurs when the defending team deliberately throws four pitches outside the strike zone to bypass a strong hitter. Since 2017, MLB allows managers to signal an intentional walk without throwing the pitches.

How BB Impacts Player and Team Performance

A high number of walks (BB) indicates plate discipline and can be a hallmark of elite hitters. Conversely, a high walk count for a pitcher suggests poor command.

Player	Year	Team	BB (Walks)	OBP	BB% (Walk Percentage)
Barry Bonds	2004	San Francisco Giants	232	.609	34.1%
Babe Ruth	1923	New York Yankees	170	.545	28.7%
Joe Morgan	1975	Cincinnati Reds	132	.466	21.2%
Shohei Ohtani	2023	Los Angeles Angels	102	.390	12.7%
Mike Trout	2020	Los Angeles Angels	98	.490	23.8%

Table data source:1, 2

The data shows a strong correlation between high walk totals and on-base percentage (OBP). Barry Bonds’ 2004 season remains the gold standard, with 232 walks contributing to a record .609 OBP. Elite players often maintain walk rates above 15%, indicating exceptional plate discipline.

Walks and Pitching Statistics

For pitchers, walks are tracked using BB/9 (walks per nine innings). A lower BB/9 indicates better control. League average BB/9 in 2024 was approximately 3.0, while elite starters often post rates below 2.0.

Frequently Asked Questions About BB in Baseball

What does BB stand for in baseball statistics?

BB stands for 'base on balls,' which means a batter walked after receiving four pitches outside the strike zone.

Does a walk (BB) count as an at-bat?

No, a walk does not count as an at-bat, so it does not affect a player's batting average, but it does count toward on-base percentage (OBP).

What is the difference between BB and IBB?

BB refers to any walk, while IBB (intentional base on balls) specifically denotes a walk issued deliberately by the defense to avoid facing a strong hitter.

Can a walk win a game in baseball?

Yes, if the bases are loaded and a walk forces a run to score, it results in a 'walk-off' play, ending the game immediately if it’s the home team in the final inning.

How does a walk affect a pitcher's ERA?

A walk itself does not directly impact ERA, but it increases the likelihood of runs scoring, which does raise a pitcher's ERA if those runners come around to score.