What is BB in Baseball?
Walks (Base on Balls) · Batting
A walk, or base on balls (BB), is awarded to a batter who receives four pitches outside the strike zone that the batter does not swing at. The batter is awarded first base without the threat of being put out. Walks reflect a batter's plate discipline — their ability to lay off bad pitches and make the pitcher throw strikes. An intentional walk (IBB) is a strategic decision by the manager to put the batter on base deliberately.
Formula
BB = Total pitches outside strike zone taken (four per walk)
BB% = Walks ÷ Plate Appearances. A player with 100 walks in 650 plate appearances has a BB% of 15.4%. The league-average BB% is typically around 8–9%. Elite walk rates exceed 13–15%.
Benchmarks
| Level | BB |
|---|---|
| Elite (season) | 100+ |
| Excellent (season) | 80–99 |
| Good (season) | 60–79 |
| Average (season) | 40–59 |
| All-Time Great (career) | 1,500+ |
ALL-TIME CAREER BB LEADERS
| Rank | Player | BB |
|---|---|---|
| 1 | Barry Bonds | 2558 |
| 2 | Rickey Henderson | 2190 |
| 3 | Babe Ruth | 2062 |
| 4 | Ted Williams | 2021 |
| 5 | Joe Morgan | 1865 |
| 6 | Carl Yastrzemski | 1845 |
| 7 | Jim Thome | 1747 |
| 8 | Mickey Mantle | 1733 |
| 9 | Mel Ott | 1708 |
| 10 | Frank Thomas | 1667 |
BEST SINGLE-SEASON BB IN MLB HISTORY
| Rank | Player | Year | Team | BB |
|---|---|---|---|---|
| 1 | Barry Bonds | 2004 | SFG | 232 |
| 2 | Barry Bonds | 2002 | SFG | 198 |
| 3 | Barry Bonds | 2001 | SFG | 177 |
| 4 | Babe Ruth | 1923 | NYY | 170 |
| 5 | Mark McGwire | 1998 | STL | 162 |
| 6 | Ted Williams | 1947 | BOS | 162 |
| 7 | Ted Williams | 1949 | BOS | 162 |
| 8 | Ted Williams | 1946 | BOS | 156 |
| 9 | Barry Bonds | 1996 | SFG | 151 |
| 10 | Eddie Yost | 1956 | WSN | 151 |
HISTORICAL CONTEXT
The walk has been part of baseball since the 1800s, though the number of balls required varied — it was eight balls in 1880, then gradually reduced to four balls by 1889. From the beginning, the walk was understood as a positive offensive outcome, though batting average's dominance as a statistic led it to be undervalued for most of the 20th century.
"Moneyball" (2003) brought new attention to the walk's value. The Oakland Athletics, as documented by Michael Lewis, exploited the market's undervaluation of OBP — which heavily rewards walks — to build competitive teams at low cost. This accelerated the sabermetric re-evaluation of plate discipline as a core offensive skill.
Barry Bonds holds both the single-season and career walk records. His 232 walks in 2004 — driven by intentional walks as opposing teams simply refused to pitch to him — remains the single-season record by a wide margin. His career total of 2,558 walks is also an all-time record. Rickey Henderson (2,190) and Babe Ruth (2,062) rank second and third.
The walk has become increasingly valued in player development and roster construction. Teams now actively seek hitters with high BB% because plate discipline correlates with overall offensive performance and is one of the most stable year-to-year skills a hitter possesses.
ERA COMPARISON: HOW THE LEAGUE AVERAGE HAS SHIFTED
Walk rate (BB%) reflects how often hitters draw walks per plate appearance. It peaked in the Steroid Era when pitchers struggled with control, and has declined as strikeouts have risen.
| Era | Years | Lg Avg BB% (batters) |
|---|---|---|
| Dead Ball Era | 1900–1919 | 7.5% |
| Live Ball Era | 1920–1941 | 8.3% |
| Post-WWII Era | 1942–1960 | 9.4% |
| Year of the Pitcher | 1961–1968 | 8.2% |
| Expansion Era | 1969–1988 | 8.7% |
| Steroid Era | 1989–2005 | 8.9% |
| Post-Steroid Era | 2006–2019 | 8.4% |
| Modern Era | 2020–2024 | 8.5% |
BB% = walks ÷ plate appearances. Higher strikeout rates in the modern era have come partly at the expense of walks as batters swing more aggressively. Computed from Lahman historical MLB data.
FREQUENTLY ASKED QUESTIONS
What is BB in baseball?
A walk, or base on balls (BB), is awarded to a batter who receives four pitches outside the strike zone that the batter does not swing at. The batter is awarded first base without the threat of being put out. Walks reflect a batter's plate discipline — their ability to lay off bad pitches and make the pitcher throw strikes. An intentional walk (IBB) is a strategic decision by the manager to put the batter on base deliberately.
How is BB calculated?
Walks are a counting statistic tracked per plate appearance. They are included in on-base percentage (OBP) calculations but not batting average. Walk rate (BB%) — walks divided by plate appearances — measures how often a player draws a walk per trip to the plate and normalizes the stat for different workloads.
What is a good BB in baseball?
In the modern era, 80+ walks in a season is excellent; 100+ is elite; 120+ is legendary. Career walk totals above 1,500 reflect exceptional longevity and plate discipline. A BB% above 12% is elite; 9–12% is above average; below 6% indicates below-average patience at the plate.
Who has the most career walks in MLB history?
Barry Bonds holds the career walk record with 2,558, more than 300 ahead of second-place Rickey Henderson (2,190). Babe Ruth (2,062), Ted Williams (2,021), and Joe Morgan (1,865) round out the top five. Bonds also holds the single-season record with 232 walks in 2004.
What is the difference between BB and IBB?
BB (base on balls) includes all walks — both those resulting from a pitcher missing the strike zone and intentional walks (IBB). IBB (intentional base on balls) is a separate statistic tracking walks issued intentionally by the defense as a strategic decision, typically to face a weaker hitter or to set up a force out. Barry Bonds holds the single-season IBB record with 120 in 2004.
EXPLORE MORE STATS
Pitching
ERA
Learn more →
Batting
OPS
Learn more →
Batting
AVG
Learn more →
Batting
HR
Learn more →
Batting
RBI
Learn more →
Advanced
WAR
Learn more →
Pitching
WHIP
Learn more →
Batting
SLG
Learn more →
Batting
OBP
Learn more →
Pitching
Wins
Learn more →
Pitching
SO
Learn more →
Batting
SB
Learn more →
Pitching
SV
Learn more →
Advanced
FIP
Learn more →
Pitching
K/9
Learn more →
Pitching
BB/9
Learn more →
Advanced
BABIP
Learn more →
Advanced
wOBA
Learn more →
Advanced
PIV
Learn more →