- Slugging percentage is a calculation of the total number of bases earned over number of at bats. Unlike batting average, which treats every hit from single to home run as simply one hit, slugging percentage calculates hits based upon the number of bases earned. Therefore, a single would count as one, a double as two, a triple as three and a home run as four. To calculate a slugging percentage, you'd assign the appropriate number to each of a batter's hits and add up the total for a given time period (season, series, post season). Then divide that by the at bats and you'll get the slugging percentage. Then round to the third decimal place.
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Here is an example. John, the clean-up hitter in the lineup, had a total of 20 at bats so far this season. He struck out five times, flied out seven and grounded out three times. During the other five at bats he had two home runs, two doubles and one single.
2 (HR) x 4 (bases)= 8
2 (doubles) x 2 (bases)=4
1 (single) x 1 (base)=1
8 + 4 +1 = 13 bases total.
13 / 20 = .65
John has a slugging percentage of .650. He's hitting the ball very well, but the season's still quite early. - Unlike batting average, which is limited to one or below by the parameters of its calculation, slugging percentage is mathematically limited to 4 or below (a home run for every at bat would result in a 4). Practically speaking, no one actually hits a home run (or any hit) every at bat, unless they've had very few at bats--like one. Therefore, slugging percentages over any significant amount of time like a full season will always be less than one. So what is a good major league slugging percentage? A solid slugging percentage for a power hitter begins in the .400 range. Slugging percentages may reach the .800s in very rare instances. For instance, Barry Bonds had a .863 slugging percentage in 2001, breaking Babe Ruth's record of .847. These are the only two batters in history to have a slugging percentage over .800 (Ruth and Bonds did it twice). More commonly a good power hitter with an excellent season will hit in the .500 to .700 range. Babe Ruth holds the record for highest career slugging percentage at .690.
- It should be clear now that slugging percentage is a statistic of power. In analyzing a power hitter, usually the three, four and five spot in a lineup, it's one of the important factors in assessing performance. The simple strategy of a hitting lineup is to put hitters with the best batting average and on-base percentage (calculation of how often they got on base via hit, walk and so on) at the top of the order. The power hitters follow in the middle of the lineup with the idea that they will knock in runs. Extra-base hits are a big part of this strategy because they drive in more runs. Therefore, a hitter with a high slugging percentage is more likely to drive in runs.
- For the purpose of calculating slugging percentage, and batting average for that matter, at bats in which a hitter was walked, hit by a pitch or executed a sacrifice do not count as at bats.
