Baseball Glossary › At-Bat
At-Bat (AB)
AB stands for at-bat, an official turn at bat used to calculate batting average and slugging percentage. A batter gets an at-bat when he gets a hit, reaches on an error or fielder's choice, or makes an out. Walks, hit-by-pitches, sacrifice bunts, sacrifice flies and catcher's interference do not count as at-bats.
Formula
Worked example (illustrative numbers): a hitter has 600 plate appearances with 60 walks, 5 hit-by-pitches, 3 sacrifice bunts and 5 sacrifice flies.
Excluded trips = 60 + 5 + 3 + 5 = 73
AB = 600 - 73 = 527
Athletics example: Rickey Henderson
Rickey Henderson is a good illustration of why at-bats and plate appearances differ. He recorded 10,961 official at-bats in his career, but he also drew 2,190 walks, and none of those walks count as at-bats. See the full career line on the Rickey Henderson player page.
Hits / at-bats = 3,055 / 10,961 = .279 batting average
Career MLB totals from our player database (MLB Stats API).
What to Know
At-bat vs plate appearance: every completed trip to the plate is a plate appearance, but only some are at-bats. Under Official Baseball Rule 9.02(a)(1), no at-bat is charged for a sacrifice bunt or sacrifice fly, a walk, a hit-by-pitch, or being awarded first base for interference or obstruction.
At-bats are the denominator for batting average and slugging percentage. That is why walks never lower a batting average: they are not at-bats at all. MLB.com notes that hitters near the top of the order, and hitters who rarely walk, tend to pile up more at-bats over a season.
At-bats are also different from games played. A player can appear in a game as a pinch-runner or defensive replacement and record zero at-bats, while a leadoff hitter may get five or more in a single game.
Frequently Asked Questions
What does AB mean in baseball?
AB means at-bat. It is an official turn at bat that ends in a hit, an out, an error or a fielder's choice. At-bats are the denominator for batting average and slugging percentage.
What counts as an at-bat in baseball?
A batter is charged with an at-bat when he gets a hit, reaches on an error or fielder's choice, or makes an out that is not a sacrifice. Strikeouts, groundouts and flyouts are all at-bats.
Do walks count as at-bats?
No. A walk is a plate appearance but not an at-bat, so it does not change batting average or slugging percentage. The same is true for hit-by-pitches, sacrifice bunts, sacrifice flies and catcher's interference.
What is the difference between an at-bat and a plate appearance?
A plate appearance is every completed turn at the plate. An at-bat is the subset left after removing walks, hit-by-pitches, sacrifice bunts, sacrifice flies and interference or obstruction awards. Plate appearances are always equal to or higher than at-bats.
Does a sacrifice fly count as an at-bat?
No. Official Baseball Rule 9.02(a)(1) says no time at bat is charged for a sacrifice fly or sacrifice bunt. A sacrifice fly does still count against on-base percentage.
Does a strikeout count as an at-bat?
Yes. A strikeout is an out that is not a sacrifice, so it counts as an official at-bat and lowers batting average. That holds even if the batter reaches first on a dropped third strike.
Related Terms
Sources
- MLB.com Glossary: At-Bat (AB)
- MLB.com Glossary: Plate Appearance (PA)
- Official Baseball Rules 2026 (MLB)
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