What is SLG in Baseball?
Slugging Percentage · Batting
Slugging Percentage (SLG) measures a batter's total bases per at-bat. Unlike batting average, which treats all hits equally, slugging percentage rewards extra-base hits — doubles count as 2, triples as 3, and home runs as 4. It is a key measure of a batter's power output.
Formula
SLG = (1B + 2×2B + 3×3B + 4×HR) ÷ At-Bats
A player who goes 3-for-5 with a single (1B), double (2B), and home run (HR) has a single-game SLG of (1+2+4) ÷ 5 = 1.400. Over a full season, an SLG above .500 is considered elite.
Benchmarks
| Level | SLG |
|---|---|
| Elite | > .550 |
| Excellent | .500–.550 |
| Above Average | .440–.500 |
| Average | .380–.439 |
| Below Average | < .380 |
ALL-TIME CAREER SLG LEADERS
| Rank | Player | SLG |
|---|---|---|
| 1 | Babe Ruth | 0.690 |
| 2 | Ted Williams | 0.634 |
| 3 | Lou Gehrig | 0.632 |
| 4 | Turkey Stearnes | 0.617 |
| 5 | Mule Suttles | 0.616 |
| 6 | Aaron Judge | 0.615 |
| 7 | Jimmie Foxx | 0.609 |
| 8 | Barry Bonds | 0.607 |
| 9 | Hank Greenberg | 0.605 |
| 10 | Mark McGwire | 0.588 |
BEST SINGLE-SEASON SLG IN MLB HISTORY
| Rank | Player | Year | Team | SLG |
|---|---|---|---|---|
| 1 | Mule Suttles | 1926 | SLS | 0.877 |
| 2 | Barry Bonds | 2001 | SFG | 0.863 |
| 3 | Babe Ruth | 1920 | NYY | 0.849 |
| 4 | Babe Ruth | 1921 | NYY | 0.846 |
| 5 | Barry Bonds | 2004 | SFG | 0.812 |
| 6 | Barry Bonds | 2002 | SFG | 0.799 |
| 7 | Babe Ruth | 1927 | NYY | 0.772 |
| 8 | Lou Gehrig | 1927 | NYY | 0.765 |
| 9 | Babe Ruth | 1923 | NYY | 0.764 |
| 10 | Rogers Hornsby | 1925 | STL | 0.756 |
HISTORICAL CONTEXT
Slugging percentage has been tracked since the 1870s but gained prominence as a meaningful statistic in the 1950s and 1960s as analysts sought to capture power production more accurately than batting average could.
Babe Ruth holds the all-time career slugging percentage record at .6897 — no other player is above .635. This reflects Ruth's unprecedented combination of home run power and overall hit quality.
Barry Bonds posted the highest single-season slugging percentage in history with .863 in 2001, driven by a record 73 home runs. Other legendary single-season marks include Babe Ruth's .847 (1920) and .772 (1921).
SLG is a component of OPS (On-Base Plus Slugging), the most widely used composite offensive metric in modern baseball analysis. On its own, SLG is somewhat limited because it does not account for plate discipline — a batter who walks frequently is more valuable than SLG alone indicates.
ERA COMPARISON: HOW THE LEAGUE AVERAGE HAS SHIFTED
League-average slugging percentage climbed sharply with the introduction of the lively ball in the 1920s and again during the Steroid Era.
| Era | Years | Lg Avg SLG |
|---|---|---|
| Dead Ball Era | 1900–1919 | .332 |
| Live Ball Era | 1920–1941 | .397 |
| Post-WWII Era | 1942–1960 | .380 |
| Year of the Pitcher | 1961–1968 | .373 |
| Expansion Era | 1969–1988 | .382 |
| Steroid Era | 1989–2005 | .414 |
| Post-Steroid Era | 2006–2019 | .412 |
| Modern Era | 2020–2024 | .406 |
Figures represent MLB combined league-average slugging percentage per era. Computed from Lahman historical MLB data.
FREQUENTLY ASKED QUESTIONS
What is SLG in baseball?
Slugging Percentage (SLG) measures a batter's total bases per at-bat. Unlike batting average, which treats all hits equally, slugging percentage rewards extra-base hits — doubles count as 2, triples as 3, and home runs as 4. It is a key measure of a batter's power output.
How is SLG calculated?
Slugging percentage is calculated by assigning each type of hit its total base value (1 for singles, 2 for doubles, 3 for triples, 4 for home runs), summing those values, and dividing by official at-bats. Walks, HBP, and sacrifice flies are not included.
What is a good SLG in baseball?
A slugging percentage above .500 is elite; .450–.499 is excellent; .400–.449 is above average; .350–.399 is average. The league-average SLG is typically around .410–.430. Power hitters in the middle of the order typically post .500+ SLG.
Who has the highest career slugging percentage in MLB history?
Babe Ruth holds the career slugging percentage record at .6897. Ted Williams (.6338) and Lou Gehrig (.6324) are second and third. Among players active since 1980, Barry Bonds (.6069) leads the career list.
Can a slugging percentage be over 1.000?
Yes, in theory. A player who hits a home run every at-bat would have a 4.000 SLG. In a single game, players occasionally post SLG over 1.000 (e.g., hitting two home runs in two at-bats = 8 total bases ÷ 2 AB = 4.000 SLG for the game). Over a full season, no player has ever posted a 1.000+ SLG, though Barry Bonds came close in his best stretches.
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