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. 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.
- SLG (Slugging Percentage):
- Total bases divided by at bats — a measure of power rather than frequency.
Data updated
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 | .690 |
| 2 | Ted Williams | .634 |
| 3 | Lou Gehrig | .632 |
| 4 | Turkey Stearnes | .617 |
| 5 | Mule Suttles | .616 |
| 6 | Aaron Judge | .610 |
| 7 | Jimmie Foxx | .609 |
| 8 | Barry Bonds | .607 |
| 9 | Hank Greenberg | .605 |
| 10 | Mark McGwire | .588 |
BEST SINGLE-SEASON SLG IN MLB HISTORY
Background bands show historical MLB eras. Click a dot to view the player.
| Rank | Player | Year | Team | SLG |
|---|---|---|---|---|
| 1 | Barry Bonds | 2001 | SFN | .863 |
| 2 | Babe Ruth | 1920 | NYA | .849 |
| 3 | Babe Ruth | 1921 | NYA | .846 |
| 4 | Barry Bonds | 2004 | SFN | .812 |
| 5 | Barry Bonds | 2002 | SFN | .799 |
| 6 | Babe Ruth | 1927 | NYA | .772 |
| 7 | Lou Gehrig | 1927 | NYA | .765 |
| 8 | Babe Ruth | 1923 | NYA | .764 |
| 9 | Rogers Hornsby | 1925 | SLN | .756 |
| 10 | Mark McGwire | 1998 | SLN | .752 |
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 .690 — no other player is above .635. This reflects Ruth's unprecedented combination of home run power and overall hit quality.
Mule Suttles posted the highest single-season slugging percentage on record at .877 for the 1926 St. Louis Stars. Barry Bonds's .863 in 2001, driven by a record 73 home runs, is the highest mark of the modern era, followed by Babe Ruth's .849 (1920) and .846 (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.
SLG: 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 .550 is elite; .500–.550 is excellent; .440–.500 is above average; .380–.439 is average; below .380 is below 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 all-time career slugging Percentage record at .690, followed by Ted Williams (.634), Lou Gehrig (.632), Turkey Stearnes (.617), and Mule Suttles (.616).
- 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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