Baseball Glossary › Slugging Percentage
Slugging Percentage (SLG)
Slugging percentage (SLG) is the average number of bases a hitter gains per at-bat. It is total bases divided by at-bats, so a single counts 1, a double 2, a triple 3 and a home run 4. Walks are left out. SLG measures power, and it is written like .450 rather than as a true percentage.
Formula
Worked example (illustrative numbers): a hitter has 100 singles, 30 doubles, 2 triples and 25 home runs in 550 at-bats.
Total bases = 100 + (2 x 30) + (3 x 2) + (4 x 25) = 266
SLG = 266 / 550 = .484
Athletics example: Jimmie Foxx
Hall of Famer Jimmie Foxx, a Philadelphia Athletics star, finished his career with 2,646 hits in 8,134 at-bats: 1,529 singles, 458 doubles, 125 triples and 534 home runs. See the full career line on the Jimmie Foxx player page.
Total bases = 1,529 + (2 x 458) + (3 x 125) + (4 x 534) = 4,956
SLG = 4,956 / 8,134 = .609
That matches the .609 career slugging percentage on his player page. Career MLB totals from our player database (MLB Stats API).
What to Know
Slugging percentage is not a percentage in the everyday sense. Because a home run is worth four bases, SLG can in theory reach 4.000, though over a full season even the best power hitters land far below 1.000. Read it as bases per at-bat.
SLG vs batting average: batting average counts every hit the same, so a single and a home run both add one hit. Slugging gives the home run four times the weight of a single, which is why a .250 hitter with power can out-slug a .300 hitter who mostly singles. SLG vs OPS: OPS adds slugging to on-base percentage so one number captures both power and getting on base.
What counts as a good SLG depends on the league's run environment in a given year, so compare a hitter with his league rather than with a fixed cutoff. A quick way to see pure power is isolated power, which is simply SLG minus batting average.
Frequently Asked Questions
What is slugging percentage in baseball?
Slugging percentage (SLG) is the number of total bases a hitter records per at-bat. A single is one base, a double two, a triple three and a home run four, so SLG rewards power in a way batting average does not.
How do you calculate slugging percentage?
Add up total bases (singles, plus 2 times doubles, plus 3 times triples, plus 4 times home runs) and divide by at-bats. For example, 266 total bases in 550 at-bats is a .484 slugging percentage.
Do walks count in slugging percentage?
No. Slugging percentage only uses hits and at-bats. Walks, hit-by-pitches and sacrifices are not at-bats and add no total bases, so they do not affect SLG. On-base percentage is the stat that credits walks.
What is the difference between slugging percentage and batting average?
Batting average is hits divided by at-bats, so every hit counts the same. Slugging percentage is total bases divided by at-bats, so extra-base hits count more. Two hitters with the same average can have very different slugging percentages.
Is slugging average the same as slugging percentage?
Yes. Slugging average, slugging and SLG are all names for the same stat: total bases divided by at-bats. The Official Baseball Rules call it slugging percentage.
What is the highest possible slugging percentage?
The theoretical maximum is 4.000, which would mean a home run in every at-bat. In practice, a full-season slugging percentage above .600 is rare and marks one of the best power seasons in the league.
Related Terms
Sources
- MLB.com Glossary: Slugging Percentage (SLG)
- MLB.com Glossary: Total Bases (TB)
- Official Baseball Rules 2026 (MLB)
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