Innings pitched (IP)

A pitcher earns a third of an inning for every out made while they are pitching, however the out was made: a strikeout, a groundout, a runner caught stealing or picked off. Three outs make one inning pitched. Outs are what count, not batters faced or pitches thrown, so a pitcher who faces six batters and gets one out has pitched a third of an inning.

The dot in a box score is shorthand, not a decimal. 4.1 is four innings and one out, 4.2 is four innings and two outs, and the next out makes it 5.0. There is never a 4.3. When you add up a staff's innings, add the outs: 2.2 plus 1.1 is eight outs plus four outs, twelve outs, which is 4.0.

The decimal shorthand trips up stat math. Before you use innings pitched in a formula, turn the thirds into real fractions: 4.1 becomes 4.333 and 4.2 becomes 4.667. A pitcher with 2 earned runs in 4.2 innings of a seven-inning game has an ERA of 2 × 7 ÷ 4.667, which is 3.00. Our ERA calculator takes innings the way a box score writes them (4.2) and converts them for you.

A pitcher who leaves in the middle of an inning keeps the outs they recorded, and any runners they left on base stay theirs: if those runners score, the runs are charged to the pitcher who put them on, not to the reliever. On a pitching chart, write the outs as they happen and mark the batter the pitcher left with, so the line is right at the end of the game.

Examples

• A starter gets two outs in the sixth and is taken out: 5.2 IP (5⅔ innings).
• A reliever faces three batters, walks one and gets two groundouts: 0.2 IP.
• A runner is caught stealing for the third out: the pitcher gets the third of an inning.
• Two pitchers throw 3.1 and 3.2 innings: 10 + 11 = 21 outs, 7.0 innings for the game.

Put it on a card: Pitching charts.

Frequently Asked Questions

More in the glossary

• Earned run
• Putout and assist (PO, A)
• Stolen base and caught stealing (SB, CS)
• All glossary pages