Baseball Glossary › Walk Rate
Walk Rate (BB%)
Walk rate (BB%) is the share of plate appearances that end in a walk. For a hitter it is walks divided by plate appearances; for a pitcher it is walks divided by batters faced. BB stands for base on balls. A high BB% signals a patient hitter, while a low BB% signals a pitcher with good control.
Formula
Worked example (illustrative numbers): a hitter draws 60 walks in 600 plate appearances.
BB% = 60 / 600 = 0.100, or 10.0 percent
What to Know
BB% uses plate appearances rather than at-bats because walks are not at-bats. Its partner stat is strikeout rate, and the two together give a quick read on a hitter's plate discipline. Walks also feed straight into on-base percentage, which is why a hitter with a high walk rate can keep his OBP up during a slump.
FanGraphs publishes a rough rule of thumb for hitters, while stressing that league averages shift from year to year: around 8 percent is about average, 10 percent above average, 12.5 percent great and 15 percent excellent, with 5.5 percent or lower in poor territory.
For pitchers the scale is reversed and lower is better. Walk rate per batter faced is the more precise cousin of walks per nine innings, because it is not affected by how many batters a pitcher faces in an inning.
Frequently Asked Questions
What does BB mean in baseball stats?
BB stands for base on balls, the official name for a walk. A batter walks when he takes four pitches outside the strike zone that he does not swing at. BB% is the share of plate appearances that end in a walk.
How do you calculate walk rate?
For a hitter, divide walks by plate appearances. 60 walks in 600 plate appearances is a 10.0 percent walk rate. For a pitcher, divide walks allowed by total batters faced.
What is a good walk rate for a hitter?
FanGraphs' rule of thumb puts about 8 percent at average, 10 percent above average and 12.5 percent great, with 15 percent excellent. League averages change over time, so compare a hitter with his own season's league.
Why does BB% use plate appearances instead of at-bats?
Walks do not count as at-bats, so dividing by at-bats would leave the walks out of the denominator. Plate appearances count every trip to the plate, which makes the rate an honest share.
Is walk rate the same as BB/9?
No. BB% is walks per batter faced, while BB/9 is walks per nine innings pitched. They usually move together, but BB% is more precise because it does not depend on how many batters came up each inning.
Does an intentional walk count in BB%?
In the basic formula, yes: walks include intentional walks. Some analysts remove intentional walks to focus on plate discipline, so check which version a site is showing.
Related Terms
Sources
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