Strikeout-to-walk ratio

In baseball statistics, strikeout-to-walk ratio (K/BB) is a measure of a pitcher's ability to control pitches, calculated as strikeouts divided by bases on balls.

A hit by pitch is not counted statistically as a walk and therefore not counted in the strikeout-to-walk ratio.

The inverse of this calculation is the related statistic for hitters, walk-to-strikeout ratio (BB/K).


Through May 24, 2019, the all-time career leaders among starting pitchers are Chris Sale (5.30), Tommy Bond (5.04), and Corey Kluber (5.00).[1]

Through May 22, 2019, the all-time career leaders among relievers are Koji Uehara (7.94), Sean Doolittle (6.41), and Roberto Osuna (6.33).[2]

Single-season leader Phil Hughes (11.625 K/BB ratio).

The player with the highest single regular season K/BB ratio through 2018 was Minnesota Twins pitcher Phil Hughes in 2014, with a ratio of 11.625 (186 strikeouts and 16 walks).[3] He is followed by Bret Saberhagen (11.00 in 1994) and Cliff Lee (10.28 in 2010).[4] Despite pitching only 149 innings in 2016, Clayton Kershaw set a new record for K/BB ratio by striking out 172 batters while walking only 11 for a ratio of 15.6.

A pitcher who possesses a great K/BB ratio is usually a dominant power pitcher, such as Randy Johnson, Pedro Martínez, Curt Schilling, or Mariano Rivera. However, in 2005, Minnesota Twins starting pitcher Carlos Silva easily led the major leagues in K/BB ratio with 7.89:1, despite striking out only 71 batters over 188⅓ innings pitched; he walked only nine batters.[5]


  1. ^ Career Leaders &amp Records for Strikeouts / Base On Balls |
  2. ^
  3. ^ "Hughes Loses 500k Bonus Due to Rain Delay". Retrieved 24 September 2014.
  4. ^ Single-Season Leaders &amp Records for Strikeouts / Base On Balls |
  5. ^ "MLB Player Pitching Stats -2005". ESPN. Retrieved 5 July 2013.