Slugging percentage is the number of bases a batter records per official at-bat. It represents a measure of the batter’s overall power output at the plate and can range from a low of 0.000 to a high of 4.000.
How is slugging percentage calculated?
To calculated a batter’s slugging percentage, add the number of bases he collects from all hits and divide that total by the number of official at-bats he records. In other words:
Slugging Percentage = TotalBases/At-Bats
In this formula, you calculate total bases like this:
TotalBases = 1.0*(number of singles) + 2.0*(number of doubles) + 3.0*(number of triples) + 4.0*(number of home runs)
Or, in a more shorthand form:
TotalBases = 1B + 2*2B + 3*3B + 4*HR
Putting it all together, we have the full formula for slugging percentage:
Slugging Percentage = (1B + 2*2B + 3*3B + 4*HR)/At-Bats
Generally speaking, a slugging percentage (SLG) of .450 or better puts a batter in the upper half of the league in power production.