Glossary

On-base plus slugging (OPS)

A baseball hitting stat adding on-base percentage and slugging percentage into a single number summarizing overall production.

Also called: OPS

On-base plus slugging combines two established baseball rate stats, on-base percentage, how often a batter reaches base, and slugging percentage, total bases per at-bat, into one number meant to summarize overall offensive contribution more completely than batting average alone.

The formula is simply OPS = OBP + SLG. Because the two components are added rather than weighted by their actual relationship to run scoring, OPS implicitly treats one point of OBP as equal in value to one point of SLG, even though run-estimation research shows on-base ability contributes somewhat more to scoring runs than slugging does. More refined stats such as weighted on-base average correct this by weighting each offensive event by its measured run value.

OPS became popular because it is easy to calculate from stats every scoreboard already shows and correlates well with run production, a major improvement over batting average, which ignores walks and extra-base power entirely. League- and park-adjusted versions such as OPS+ are used for cross-era and cross-park comparisons. The common pitfall is comparing raw OPS across different ballparks or seasons without adjustment, since hitter-friendly parks and high-offense eras inflate OPS independent of skill, and OPS says nothing about baserunning, defense or the batting average on balls in play luck a hitter experienced.

Last reviewed September 22, 2026

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Related terms

Batting average on balls in play (BABIP) The batting average on balls put in play, excluding home runs and strikeouts, used to gauge how much luck shaped a batting line. Fielding independent pitching (FIP) A pitching metric on the ERA scale built only from strikeouts, walks, hit-by-pitches and home runs, a pitcher's most direct outcomes. Pythagorean expectation A formula estimating a team's expected win percentage from the points or runs it scores and allows, rather than its actual record. Wins above replacement (WAR) A single number estimating how many more wins a player adds over a season than a readily available replacement-level substitute. Sabermetrics The empirical, statistics-driven study of baseball performance, valuing measurable production over traditional scouting judgment.

Related guides

How baseball analytics works How sabermetrics grew from box scores to batted-ball physics, what OPS, FIP and BABIP actually measure, and where teams still argue.