Slugging Percentage Calculator & Formula

In baseball statistics (sabermetrics), one of the most useful measures of a batter's power is his slugging percentage or slugging average, SLG. A baseball player's slugging percentage indicates the number of bases gained per time at bat. The slugging percentage of a player is not actually a percent, but a number that can in theory range from 0 and 4. Currently, the slugging percentage record is held by Barry Bonds, who earned an SLG of 0.863 in 2001.

How to Calculate Slugging Percentage

You need to know five stats of a player in order to calculate his slugging percentage: singles (1B), doubles (2B), triples (3B), home runs (HR), and at-bats (AB). The formula for SLG is then

SLG = (1B + 2*2B + 3*3B + 4*HR)/AB

The numerator of this fraction is total bases (TB). At-bats does not include bases on balls (BB), aka walks. Nor does it include any hits by pitch (HBP), sacrifice flies (SF), or sacrifice hits (SH).

Baseball stats often do not list 1B, however, you can calculate it backwards from the number of hits (H):

1B = H - 2B - 3B - HR.

Example Calculation: In 2003 Barry Bonds had 390 at-bats, 133 hits, 22 doubles, 1 triple, and 45 home runs. The five necessary stats to calculate SLG are

1B = 65
2B = 22
3B = 1
HR = 45
AB = 390

His slugging percentage is then

SLG = (65 + 2*22 + 3*1 + 4*45)/390
= 292/390
= 0.749 (stats are always rounded to 3 decimal places)

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