What Is On-Base Percentage in Softball?

On-base percentage measures the thing that actually matters at the plate: did you avoid making an out? It counts hits, walks and hit-by-pitches in the numerator, and divides by everything that isn't a sacrifice bunt.

A player who walks often can have a modest batting average and still be one of the most valuable hitters in the lineup, because outs are the scarce resource in an inning. This is why OBP is generally preferred to batting average when evaluating a hitter.

Note the denominator: it's at-bats plus walks plus hit-by-pitches plus sacrifice flies — not plate appearances exactly. Sacrifice bunts are excluded. Across the tracked rec-league sample the aggregate OBP is .578.