Baseball Stats Calculator — AVG, SLG and ERA

Why these three numbers, and what each one hides

Batting average answers one narrow question: how often does a hitter get a hit per at-bat? It ignores walks entirely and treats a bunt single and a grand slam as equal events.

Slugging fixes the second problem by weighting hits by total bases, but not the first. ERA does the equivalent job for pitchers, isolating runs the pitcher is responsible for from those handed over by fielding errors. Read together they describe contact, power and run prevention; read alone, each one flatters or punishes the wrong players.

Softball uses the same formulas with one change

Batting average and slugging percentage are calculated identically in softball. The only adjustment is ERA, where a regulation game is seven innings rather than nine, so the multiplier changes. Set innings per game to 7 in the ERA section and the result is directly comparable with other softball pitchers.

What counts as good has moved over time

Benchmarks in baseball are not fixed. League-average batting average sat above .270 in the late 1990s and has drifted toward .245 in recent seasons as strikeout rates climbed, while league ERA has moved with it.

So judge a number against its era and league rather than an absolute. The table below gives modern reference points; a .260 hitter today is closer to average than the same figure would have been thirty years ago.

Modern benchmarks for hitters and pitchers

Approximate reference points for recent Major League seasons. OPS is on-base percentage plus slugging. Softball and amateur leagues run on different scales, so compare within your own competition.