Slugging Percentage Is Total Bases per At-Bat, Not a Percentage
How SLG is calculated from singles, doubles, triples and home runs, why it can top 1.000, what it ignores, and Aaron Judge's 2024 line worked step by step.
Slugging percentage (SLG) is total bases from hits divided by at-bats. A single counts one base, a double two, a triple three, a home run four; add them up and divide by at-bats. Aaron Judge’s 2024 line of 180 hits (36 doubles, one triple, 58 home runs) in 559 at-bats works out to 392 total bases and a .701 SLG. Batting average treats every hit as one hit; SLG is the stat that separates a singles hitter from a power hitter.
Despite the name, SLG is a rate, not a percentage. A .540 SLG means .540 total bases from hits per at-bat, not success in 54 percent of at-bats. Walks, hit-by-pitches, sacrifices, stolen bases and any advance after the hit add nothing to it.
Enter at-bats, hits and extra-base hits; singles, total bases and SLG update as you type.
Slugging Percentage Calculator
| Hit | Count | Bases each | Total bases |
|---|---|---|---|
| Singles | 85 | 1 | 85 |
| Doubles | 36 | 2 | 72 |
| Triples | 1 | 3 | 3 |
| Home runs | 58 | 4 | 232 |
| Total | 180 | — | 392 |
Singles are derived as H − 2B − 3B − HR. Default line: Aaron Judge, 2024 (180 H, 36 2B, 1 3B, 58 HR, 559 AB) per Baseball-Reference; formula per the MLB glossary.
The Formula: Total Bases Divided by At-Bats
If a stat line already lists total bases (TB), the calculation is one division: SLG = TB ÷ AB.
If it does not, use the expanded form: SLG = (1B + 2 × 2B + 3 × 3B + 4 × HR) ÷ AB.
| Hit | Total bases |
|---|---|
| Single | 1 |
| Double | 2 |
| Triple | 3 |
| Home run | 4 |
The denominator is at-bats, not plate appearances. These weights and the expanded formula are set out in the MLB slugging-percentage glossary.
Most stat lines show hits but not singles. Derive singles by subtracting the extra-base hits from total hits: 1B = H − 2B − 3B − HR. A hitter with 100 hits including 20 doubles, five triples and 15 home runs has 60 singles.
“Total bases” has a narrow meaning here: only bases credited to the batter through the hit itself. A double is two total bases the moment it lands. A single followed by an advance to second on a wild pitch stays a single, worth one total base; the advance belongs to the baserunning play, not the hit.
SLG is conventionally shown to three decimal places.
Worked Example: Aaron Judge’s 2024 Season
Judge’s 2024 line: 180 hits, 36 doubles, one triple, 58 home runs, 559 at-bats.
Singles: 180 − 36 − 1 − 58 = 85.
Total bases: 85 + (2 × 36) + (3 × 1) + (4 × 58) = 85 + 72 + 3 + 232 = 392.
SLG: 392 ÷ 559 = .701.
That matches the .701 on his Baseball-Reference stat line. The example shows the arithmetic; it is not a benchmark. Judge’s figure came from one player in one league and season, and it says nothing about what counts as a good SLG elsewhere.
What Counts and What Does Not
Only bases produced by hits enter the numerator. Walks and hit-by-pitches add no total bases and are not charged as at-bats, so they leave SLG untouched. Sacrifice bunts and sacrifice flies are also outside the calculation because they are not at-bats.
Baserunning after the hit never changes its value. A batter who singles and steals second still has a single worth one base; the stolen base does not turn it into a double. The same holds when a runner advances on an error, wild pitch, passed ball or a teammate’s hit. Those plays matter to the game, but they do not touch the original hitter’s SLG.
How SLG Differs From Batting Average, OBP and OPS
Each familiar hitting statistic answers a different question:
| Statistic | Measures | Power treatment |
|---|---|---|
| Batting average | Hits per at-bat | Every hit equal |
| SLG | Total bases per at-bat | Extra-base hits weighted |
| OBP | How often a hitter reaches base | Not measured |
| OPS | OBP + SLG | Combined with on-base ability |
Two hitters can share a batting average and have very different slugging percentages. Give each 30 hits in 100 at-bats and both bat .300. If one hits mostly singles and the other piles up doubles and home runs, the second has the higher SLG.
On-base percentage covers what SLG ignores: reaching base by walk or hit-by-pitch. OPS adds the two rates together, OPS = OBP + SLG, for a quick read on both on-base ability and power.
SLG is not a complete measure of offense. It omits every non-hit way of reaching base, and its one-to-four weighting is a count of credited bases, not a measure of run value. A double is worth twice a single in SLG; it is not worth exactly twice as much to run scoring.
Reading an SLG in Context
Slugging percentage can exceed 1.000 whenever a hitter averages more than one total base per at-bat: 12 total bases in 10 at-bats is a 1.200 SLG.
The possible range runs from .000 to 4.000. A hitter with no total bases sits at .000. Reaching 4.000 would take a home run in every at-bat, since four is the most bases one hit can produce. The range follows directly from the formula.
There is no fixed threshold that makes an SLG good or elite. The comparison that matters is against the same league and season. Ballpark dimensions, the scoring environment, level of competition and sample size all move a raw slugging percentage.
Era matters too. The arithmetic has never changed: total bases divided by at-bats. The conditions that produced those bases have changed a great deal, and the same raw SLG from two different periods is not automatically the same performance.
The rule to carry: add the bases credited for every hit, divide by at-bats, read the result as a power indicator rather than a literal percentage, and compare it only within the conditions that produced it.