At Bats AB

AB stands for at bats in baseball. A plate appearance that ended in a hit or an out. Walks, hit-by-pitches, sacrifice flies and sacrifice bunts are plate appearances but not at-bats, which is why a batter can come up five times and be credited with three at-bats.

How AB is calculated

AB = plate appearances − walks − hit by pitch − sacrifices − catcher’s interference

Batting average divides hits by at-bats, so every walk a hitter draws leaves his average untouched. On-base percentage uses plate appearances instead, and that is the whole difference between the two numbers.

What counts as a good AB?

Half of the 448 qualified MLB players in 2026 were at or below 327.5. Clearing 574.2 put a season in the top tenth of the league.

Median: 327.5
Top 10%: 574.2
Leader: 645

By position, the median was 447.5 for 1B, 371 for SS, 345 for 2B, 328 for 3B, 326.5 for LF and 316 for DH.

Qualified: 40+ games, non-zero, 2026 regular season.