Calculating Basic Baseball Stats – Slugging Percentage (SLG) and Total Bases

If you’re a baseball fan, you probably are aware of how important statistics are to the game. A casual fan probably understands what most of the most popular statistics measure, in a general sense, but they may not know how to calculate these stats for themselves. Let’s look at a two of the most basic hitting statistics and see how they’re calculated.

Slugging Percentage (or SLG for short) is a statistic that goes beyond simply a player’s ability to get a hit or get on base, it measures his ability to get a hit and hit for power. Where batting average is ratio of hits per at bats a player gets, Slugging Percentage is the ratio of total bases to at bats.

Total Bases credits a player for extra-base hits (doubles, triples, and home runs). Put simply, a player gets a “base” for each base he reaches during a season. Singles are counted as one base, doubles two, triples three, and home runs four.

The formula for Total Bases is Singles (Total hits – 2b -3b – HR) + (2b x 2) + (3b x 3) + (HR x 4).

For hitter who has 150 total hits, 30 doubles, 1 triple, and 10 HR, the equation would look like this:

108 (150 – 30 -2 – 10) + 60 (30 x 2) + 6 (2 x 3) + 40 (10 x 4) = 240 Total Bases

Now, to calculate Slugging Percentage (SLG), take total bases and divide by the number of at bats a hitter has. For example, say the hitter above got those 240 Total Bases in 500 at bats. You’d calculate the equation like this:

240 Total Bases / 500 At Bats = .480 SLG

Slugging Percentage is displayed as a decimal, with three spaces after the decimal point.

Now, what makes a good Slugging Percentage? Well, it’s generally accepted that a .500 Slugging Percentage is pretty darn good. Of course, that doesn’t mean a hitter with an SLG lower than that isn’t a good hitter, or that you’d always want to pick a hitter purely on his Slugging Percentage (or power). There are other things to keep in mind (such as how often a player walks and how often he strikes out) that are captured in other statistics.

Slugging percentage and Total Bases both favor a hitter who hits for both high average and for power. For example, in 2005, the leaders in Total Bases were Derrek Lee of the Chicago Cubs in the National League with 393, and Mark Teixeira of the Texas Rangers in the American League with 370. Both hit for high average (Lee led the NL with a .335 batting average, and Teixeira hit .301) and power (Lee had 50 doubles, 3 triples, and 46 HR, and Texeira 41 doubles, 3 triples, and 43 HR).

Lee also led the National League in Slugging Percentage in 2005, with a .662 SLG. This is not at all surprising when you see that he lead the league in Batting Average, Hits, and Extra Base Hits, and played in all 162 of the Cubs games. In the American League, Alex Rodriguez of the New York Yankees led the league in SLG with a .610 mark. Rodriquez hit .321 with 194 hits, 29 doubles, 1 triple, and 48 home runs. He was second in the league in Total Bases, first in Home Runs, and played in all 162 of the Yankees games.

Babe Ruth accumulated the highest single season Total Base tally in 1921, when he had 457 Total Bases on 204 hits, 44 doubles, 16 triples, and 59 Home Runs. The all-time career leader in Total Bases is Hank Aaron with 6856. Ruth is 5th on the list with 5793.

The highest single season Slugging Percentage is owned by Barry Bonds, who in 2001 put up an amazing .8634 mark. Bonds had 156 hits, 32 doubles, 2 triples, and 73 Home Runs. Amazingly, Babe Ruth and Bonds hold the top six all-time high SLG seasons between them, plus number eight all time. Babe Ruth also holds the all time career mark for Slugging Percentage, with .6898.

Slugging percentage is a great indication of a hitter’s ability to hit for high average and with power.