Key takeaways
- Read any plus stat as a percentage of league average after park and league adjustments: 100 is average, 120 is about 20 points better.
- Prefer wRC+ when OPS+ and wRC+ disagree about an on-base specialist or a free-swinging slugger, because wRC+ weights each outcome by its run value while OPS treats on-base and slugging points equally.
- Remember that ERA+ runs upward (higher is better) while ERA- runs downward, and that the two are not mirror images of each other.
- Never use OPS+ or wRC+ to compare players at different positions without a positional adjustment; neither one includes it.
- Check which publisher's version you are reading, since each uses its own park factors and league baselines.
OPS+ and wRC+ answer the same question — how much better or worse than league average was this hitter, once his ballpark and league are accounted for? — and both put league average at 100. The difference is the raw material. OPS+ starts from on-base percentage plus slugging, the version published by Baseball-Reference. wRC+ starts from weighted on-base average, FanGraphs' measure that values each kind of hit and walk by what it is worth in runs. ERA+ applies the same "100 is average" idea to pitchers, with higher numbers better.
MLB.com's glossary says a hitter's wRC+ and OPS+ for a season "will almost always look very similar." The interesting cases are the ones where they do not, and those come down to three things: how each stat weights its inputs, which park factors it uses, and a quirk in the OPS+ arithmetic.
The shared idea: a percentage of league average
Raw statistics move with the environment. A given OPS means more in a low-scoring season than in a high-scoring one, and more in a park where the ball dies than in one where it carries. The plus stats remove both effects and re-centre the result on 100.
FanGraphs explains the reading for wRC+: "every point above 100 is a percentage point above league average," so 125 means a hitter created 25 percent more runs than an average hitter would have in the same number of plate appearances, and 80 means 20 percent fewer. MLB.com uses the same language for OPS+, where 150 is 50 percent better than average.
What a park factor is
All three stats lean on a park factor. MLB.com's glossary describes the basic version: runs scored by a team and its opponents in its home park, divided by runs scored by the team and its opponents in its road games, "ever-so-slightly adjusted" when the opponents faced at home and away differ. The same exercise can be done for home runs, doubles or any other event.
As a hypothetical: if 10 percent more runs score in a club's home games than in its road games, its basic run park factor is about 1.10. A hitter who plays half his games there is credited a little less for the same raw line; a pitcher is credited a little more. The method is sound for the reason MLB.com gives — the same teams play in other parks, so the ratio isolates the building — but each publisher computes its own figures, which is the first source of disagreement between them.
OPS+: on-base and slugging, re-scaled
MLB.com gives the core formula as:
OPS+ = 100 × (OBP ÷ lgOBP + SLG ÷ lgSLG − 1)
Baseball-Reference, where OPS+ is published, describes its park handling in its batting glossary. Rather than dividing the result by a park factor — which it says is how the older Total Baseball "PRO+" appeared to work — it estimates what a league-average hitter would have produced in the player's park and uses those park-specific league baselines (written lgOBP* and lgSLG*) in the same formula. Its league baseline is built with pitchers' hitting removed.
The arithmetic quirk worth knowing
Notice that the formula adds two ratios. Take a hypothetical hitter whose on-base percentage and slugging percentage are each exactly 10 percent above the league's:
- OBP ÷ lgOBP = 1.10
- SLG ÷ lgSLG = 1.10
- OPS+ = 100 × (1.10 + 1.10 − 1) = 120
His raw OPS is only 10 percent above the league's, yet his OPS+ reads 120, because the two advantages are added together. That is not an error — it is what the formula is designed to do — but it means "20 percent better than average" in OPS+ is a convention for reading the scale, not a statement that his OPS was 20 percent higher.
wRC+: runs, weighted by what each event is worth
FanGraphs builds wRC+ in stages, starting from wOBA, which its library credits to Tom Tango. wOBA multiplies each way of reaching base by a weight. In the example FanGraphs gives for the 2013 season, a single was weighted 0.888, a double 1.271 and a home run 2.101, with walks and hit batters weighted below a single; it stresses that the weights change every year.
From wOBA, FanGraphs converts to runs above average per plate appearance (wRAA), then applies the park and league adjustments:
wRC+ = (((wRAA ÷ PA + lgR/PA) + (lgR/PA − PF × lgR/PA)) ÷ (league wRC/PA, excluding pitchers)) × 100
In words: the hitter's runs per plate appearance, plus a park correction that adds or subtracts runs depending on how friendly his home park is, divided by the runs per plate appearance of non-pitchers in his league (AL or NL), times 100.
The weighting is the point. FanGraphs' OPS entry says on-base percentage is roughly 1.8 times as valuable as slugging in its effect on run scoring, so OPS — which counts a point of each equally — "overrates power hitters and underrates high-OBP guys." wOBA does not have that problem, which is why FanGraphs recommends wRC+ over OPS+.
Why OPS+ and wRC+ can disagree about one hitter
| Reason | Effect |
|---|---|
| Input weighting | OPS gives slugging the same weight per point as on-base percentage, so an on-base specialist tends to look better by wRC+ and a low-walk slugger tends to look better by OPS+ |
| Extra-base hit values | Slugging counts a double as exactly two singles and a home run as four; wOBA's weights for 2013 valued a double at about 1.4 singles and a home run at about 2.4 |
| Park factors | Baseball-Reference and FanGraphs each compute their own, so the same park can carry slightly different adjustments |
| League baseline | wRC+ divides by the league's non-pitcher run rate; OPS+ uses park-adjusted league OBP and slugging |
| Formula structure | OPS+ adds two ratios; wRC+ works in runs per plate appearance |
The multiples in the second row are arithmetic on FanGraphs' 2013 weights (1.271 ÷ 0.888 and 2.101 ÷ 0.888), not a fixed rule. For most hitters the effects are small and partly cancel, which is MLB.com's point about the two usually looking alike. When they do not, the table usually tells you why.
ERA+ and its mirror, ERA-
For pitchers, MLB.com gives ERA+ as the park-adjusted league ERA, times 100, divided by the pitcher's ERA. Because the pitcher's ERA is on the bottom, a higher ERA+ is better. MLB.com's own description says it accounts for external factors like ballparks and opponents and sets 100 as league average.
FanGraphs publishes the inverse family — ERA-, FIP- and xFIP- — where 100 is still average but lower is better, and each point below 100 is a percentage point better than league average after the park adjustment. Its formula adjusts the pitcher's ERA for his park and divides by the league (AL or NL) ERA.
The two scales are not mirror images. Ignoring the park adjustment, a pitcher whose ERA is one quarter lower than the league's — say 3.00 against 4.00 — has an ERA- of 75 but an ERA+ of 133 (4.00 ÷ 3.00 × 100). An ERA half the league's gives an ERA- of 50 and an ERA+ of 200. ERA+ climbs faster as ERA falls, so very good pitching looks more dramatic on that scale. What is ERA in baseball covers the underlying statistic.
| Stat | Definition cited here | Built from | 100 means | Better is |
|---|---|---|---|---|
| OPS+ | MLB.com glossary; Baseball-Reference batting glossary | OBP and SLG | League average | Higher |
| wRC+ | FanGraphs library; MLB.com glossary | wOBA, converted to runs | League average (position players) | Higher |
| ERA+ | MLB.com glossary | ERA | League average | Higher |
| ERA- / FIP- | FanGraphs library | ERA or FIP | League average | Lower |
What is a good OPS+ or wRC+?
League average is always 100. Beyond that, FanGraphs publishes a rough guide for wRC+, which it describes as an estimate: about 115 counts as above average, 140 as great and 160 as excellent, while 80 is below average.
FanGraphs does not publish OPS+ on its own site, and no equivalent guide for OPS+ appears in the sources here; given MLB.com's note that the two usually land close together, the wRC+ bands are a reasonable rough reference for OPS+ too.
Three misreadings to avoid
Comparing positions. FanGraphs is explicit that wRC+ does not control for position, and neither does OPS+. A 100 from a shortstop and a 100 from a first baseman are equal at the plate and unequal in value, because the shortstop is also playing the harder position. WAR is the framework that adds the missing piece: MLB.com's glossary notes that its positional adjustment is what makes it suited to comparing players at different positions.
Treating it as clutch. FanGraphs describes wRC+ as context neutral: a hit with the bases loaded counts the same as one with the bases empty. Neither stat measures who drove in runs at the right moment.
Trusting small samples. These are rate statistics, so a hot fortnight can produce a spectacular number. The adjustments fix the environment, not the sample size.
Where this fits in our games
Plus stats exist mainly to compare players across parks, leagues and eras, and the habit they teach carries over to any stat line. In 162-0 Baseball Draft & GM Team you compare players on ERA, WHIP, home runs, on-base ability, fielding, speed and WAR, and the game's season simulator weighs roster quality and position fit alongside hitting, pitching, speed, defence and coaching. The plus-stat lesson that transfers is the weighting one: on-base ability is worth more per point than its quiet appearance on a card suggests. Our 162-0 draft guide covers the draft cards in detail.
In Baseball Career Sim 2026, your record tracks on-base percentage and slugging separately, which is more informative than a single OPS for the reasons OPS and slugging explained sets out. The wider vocabulary is in baseball stats explained for beginners, and the rest of our coverage of the sport is on the baseball hub.
Baseball Career Sim 2026 is set entirely in a fictional league with fictional teams and players. 162-0 Baseball Draft & GM Team builds its player pool from real players' careers, with ratings that are the game's own estimates. Neither is affiliated with or endorsed by any league, team, players' association or player. MLB.com, FanGraphs and Baseball-Reference are named only to identify the formulas cited. The full list of titles is under sports career and GM games.
Good to know
Frequently asked questions
What is the difference between OPS+ and wRC+?
What does wRC+ mean?
What is a good OPS+?
Is a higher ERA+ better?
What is a park factor?
Sources
- On-base Plus Slugging Plus (OPS+) | Glossary (opens in a new tab)MLB.com — accessed
- Weighted Runs Created Plus (wRC+) | Glossary (opens in a new tab)MLB.com — accessed
- Adjusted Earned Run Average (ERA+) | Glossary (opens in a new tab)MLB.com — accessed
- Ballpark Factor | Glossary (opens in a new tab)MLB.com — accessed
- wRC and wRC+ | Sabermetrics Library (opens in a new tab)FanGraphs — accessed
- OPS and OPS+ | Sabermetrics Library (opens in a new tab)FanGraphs — accessed
- wOBA | Sabermetrics Library (opens in a new tab)FanGraphs — accessed
- ERA- / FIP- / xFIP- | Sabermetrics Library (opens in a new tab)FanGraphs — accessed
- Batting Stats Glossary (opens in a new tab)Baseball-Reference.com — accessed
- Wins Above Replacement (WAR) | Glossary (opens in a new tab)MLB.com — accessed
League, team and athlete names appear here only to identify the rules, records and history being discussed. Reign Creative LLC's sports games are not affiliated with, endorsed by or licensed by any league, team, players' association or athlete, and all names and marks belong to their owners.
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