Baseball Glossary › Batting Average on Balls in Play
Batting Average on Balls in Play (BABIP)
Batting average on balls in play (BABIP) measures how often balls hit into the field of play become hits. Home runs and strikeouts are removed because the defense never touches them. League-wide BABIP almost always sits around .300, so a number far from that often points to luck or defense rather than pure skill.
Formula
Worked example (illustrative numbers): 150 hits, 20 home runs, 500 at-bats, 110 strikeouts, 5 sacrifice flies.
Numerator: 150 - 20 = 130
Denominator: 500 - 110 - 20 + 5 = 375
BABIP = 130 / 375 = .347
What to Know
For pitchers, BABIP is mostly a luck and defense indicator. FanGraphs notes it takes far longer for pitcher BABIP to stabilize than hitter BABIP, so pitchers with extreme numbers usually drift back toward league average. That is one reason FIP leaves balls in play out entirely.
For hitters, skill matters more. Fast runners and hard hitters can sustain a BABIP above .300, so FanGraphs suggests comparing a hitter with his own career BABIP rather than with the league norm. A sudden spike or drop over a month or two is usually noise.
BABIP vs batting average: batting average includes home runs and counts strikeouts as hitless at-bats. BABIP isolates only the batted balls a defense could field, which also makes exit velocity a useful companion when judging whether a hot or cold BABIP is real.
Frequently Asked Questions
What is BABIP in baseball?
BABIP stands for batting average on balls in play. It measures how often a ball hit into the field of play becomes a hit, leaving out home runs and strikeouts.
How is BABIP calculated?
Subtract home runs from hits, then divide by at-bats minus strikeouts minus home runs plus sacrifice flies. For example, 130 divided by 375 is a .347 BABIP.
What is a normal BABIP?
League-average BABIP is almost always around .300, according to both MLB and FanGraphs. Hitters with speed or very hard contact can sit above that for their whole careers.
What does a high BABIP mean?
For a pitcher, a high BABIP against often means bad luck or poor defense and tends to come down over time. For a hitter, it can be skill, but a big jump above his career norm usually signals some good fortune.
Why does BABIP exclude home runs?
Home runs leave the field of play, so no fielder has a chance to turn them into outs. Strikeouts are excluded for the same reason. BABIP focuses only on balls the defense could have fielded.
Is BABIP luck?
Partly. Luck and defense play a big role, especially for pitchers, but hitters influence their BABIP through speed and quality of contact. That is why hitters are compared with their own career BABIP.
Related Terms
Sources
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