Slugging percentage represents the total number of bases a player records per at-bat. Unlike on-base percentage, slugging percentage deals only with hits and does not include walks and hit-by-pitches in its equation.
Slugging percentage exists mainly as a response to a noticeable flaw in batting average: Not all hits are created equal. In batting average, a single and a home run are valued the same. But in slugging percentage, home runs are counted four times as much as each single. With that in mind, the formula for slugging percentage is: (1B + 2Bx2 + 3Bx3 + HRx4)/AB.
However, slugging percentage has its flaws, too, namely that a double is not worth exactly twice as much as a single -- in the context of scoring runs, at least. But slugging percentage is still one of the best evaluators of power, because it accounts for more than just home runs.
Slugging percentage can also be applied as an evaluative tool for pitchers, although this is done less frequently. In such cases, it is referred to as slugging-percentage against.
Watch: Mookie Betts collects three homers, raising his slugging percentage.
In A Call
"slugging," as a verb: "to slug"