What is OPS? Definition, Formula, and Example

OPS in Plain English

OPS stands for On-base Plus Slugging. It is the simplest popular all-in-one offensive stat: add a hitter's on-base percentage (OBP) to their slugging percentage (SLG) and read the result. A league-average MLB hitter posts roughly .720 OPS. .800 is good, .900 is All-Star territory, and 1.000+ is MVP-level production. OPS rewards hitters who do both things that score runs — get on base and hit for power — which is why it became the first sabermetric stat to reach mainstream broadcasts and the back of baseball cards.

How OPS Is Calculated

The formula has two pieces:

OBP = (Hits + Walks + Hit-By-Pitch) / (At-Bats + Walks + HBP + Sacrifice Flies)

SLG = Total Bases / At-Bats, where total bases counts a single as 1, double as 2, triple as 3, and home run as 4.

OPS = OBP + SLG

Note that OBP and SLG have different denominators, so OPS is technically not a clean rate stat — it is just an additive shorthand. Sacrifices are excluded from SLG's denominator but included in OBP's, which is part of why the next-generation metric wOBA replaced it among analysts.

Worked Example: Aaron Judge, 2024

Aaron Judge's 2024 line: .322 batting average, .458 OBP, .701 SLG. OPS = .458 + .701 = 1.159, leading MLB and the highest mark since Barry Bonds. To see how the components combine: Judge drew 133 walks (huge OBP boost) while hitting 58 home runs (huge SLG boost). A hitter with the same batting average but no walks and only singles would have an OPS in the .700s — same hits, half the value.

For contrast, Luis Arraez's 2024 .314 average produced just a .346 OBP and .398 SLG for a .744 OPS. He hit for a higher average than most of the league but generated barely above-average run production because he walked rarely and rarely hit for extra bases. OPS exposes that gap instantly.

Why OPS Matters

OPS correlates with team runs scored at roughly r = 0.94, which is why it dominated front-office and broadcast usage from the early 2000s through about 2015. It is still the default offensive number on Baseball Reference player pages, on most television graphics, and on physical baseball cards. Fantasy roto leagues frequently use OPS as a category, and DFS pricing engines lean on it because it is fast, intuitive, and stable across small samples.

Limitations and Common Misconceptions

OPS treats OBP and SLG as equally valuable, but OBP is actually about 1.8× as important to scoring runs — a walk is more valuable than a one-base increase in slugging. That is why analysts moved to wOBA and wRC+, which weight each event by its real run value and adjust for park and league. OPS also ignores park effects entirely: a 1.000 OPS in Coors Field is not the same as a 1.000 OPS in Oracle Park. Finally, OPS does not factor in baserunning or defense, so it is not a measure of total player value — that is what WAR is for.

Related Terms

• wOBA — properly-weighted offensive rate stat
• wRC+ — park- and league-adjusted offensive index
• ISO — isolated power, the slugging component minus singles
• BABIP — luck/contact-quality indicator that drives OPS variance
• WAR — total-value stat that includes offense, defense, and baserunning

In Legends Deck

OPS is one of the inputs that drives the Power and Contact ratings on Legends Deck cards. A hitter's three-year OPS is decomposed into its OBP and SLG halves, then blended with exit velocity and barrel rate to produce the final card numbers — so a high-OPS slugger like Judge gets elite Power, while a high-OPS contact hitter like Arraez (in his peak years) gets elite Contact instead.