Innings Pitched

In baseball, innings pitched (IP) are the number of innings a pitcher has completed, measured by the number of batters and base runners that are put out while the pitcher on the pitching mound in a game. Three outs made is equal to one inning pitched. One out counts as one-third of an inning, and two outs counts as two-thirds of an inning. Sometimes, the statistic is written 34.1, 72.2, or 91.0, for example, to represent 34 1⁄₃ innings, 72 2⁄₃ innings, and 91 innings exactly, respectively.

Runners left on base by a pitcher are not counted in determining innings pitched. It is possible for a pitcher to enter a game, give up several hits and possibly even several runs, and be removed before achieving any outs, thereby recording a total of zero innings pitched.