At-Bat
ABA plate appearance that ends in a hit, an out, an error, or a fielder's choice, excluding walks, hit-by-pitches, and sacrifices.
An at-bat is the denominator of batting average, which is the only reason the distinction matters. Not every trip to the plate counts as one. Walks, hit-by-pitches, sacrifice flies, sacrifice bunts, and catcher's interference are all plate appearances that are deliberately excluded.
The logic is that batting average is meant to measure what a hitter does when they are actually trying to hit. A walk is a good outcome, but it is not a swing decision the average should reward or punish, so it is set aside. That is also why a player can go 0-for-0 with three walks and see their average unchanged.
The practical consequence for youth baseball is significant. At levels where walks are common, batting average measures a shrinking share of what a player actually does, which is why on-base percentage is the more honest number below about age twelve.
Bleacher Notes charges an at-bat only when the rules call for one, so a sac fly or a walk leaves the batting average untouched while still recording the plate appearance.
What does AB mean in baseball?
AB stands for at-bat: a plate appearance that ends in a hit, an out, a reached-on-error, or a fielder's choice. It is the denominator of batting average.
What counts as an at-bat?
Hits, outs, reaching on an error, and fielder's choices all count. Walks, hit-by-pitches, sacrifice flies, sacrifice bunts, and catcher's interference do not.
Is a walk an at-bat?
No. A walk is a plate appearance but not an at-bat, so it does not change a hitter's batting average. It does raise their on-base percentage.
Let the scorebook keep itself.
Bleacher Notes scores every play from a single spoken sentence, applying these rules for you. In beta now, free for parents.