6 tools

Baseball Calculators

Pitching and hitting rate stats from a box score or season line. Innings like 6.2 are read the baseball way, and every figure shows its working.

Baseball ERA Calculator Earned run average, with 6.1 and 6.2 innings handled. 62 ER in 180.2 IP = 3.09 Baseball WHIP Calculator Walks plus hits per inning pitched. 48 BB + 155 H in 180.2 IP = 1.12 Baseball Batting Average Calculator Hits over at-bats, and what the next game does to it. 165 H in 550 AB = .300 Baseball On-Base Percentage Calculator Hits, walks and HBP over plate appearances. 230 on base in 620 = .371 Baseball Slugging Percentage Calculator Total bases per at-bat, from a normal stat line. 278 TB in 550 AB = .505 Baseball OPS Calculator On-base plus slugging, with AVG, OBP and SLG. .371 + .505 = .876

Which baseball calculator do you need?

Pitching: the ERA calculator gives earned runs per nine innings, and the WHIP calculator walks plus hits per inning.
Hitting: batting average from hits and at-bats, on-base percentage with walks and hit-by-pitches, slugging percentage from total bases, and OPS, which adds the last two together.

Why 6.2 innings is not 6.2

Innings pitched are counted in outs, and each out is a third of an inning. Box scores write 6⅓ innings as 6.1 and 6⅔ as 6.2. Typed into an ordinary calculator, 6.2 becomes six and two tenths and the ERA comes out wrong. The pitching calculators here read it the baseball way.

Where the formulas come from

Batting average, slugging percentage, earned run average and on-base percentage are defined in rule 9.21 of the Official Baseball Rules, and WHIP in MLB’s glossary. Each calculator page shows its formula, a worked example and its sources.