Like all other sports, baseball has its own set of metrics designed to communicate the effectiveness or efficiency of players in the roles, whether pitching, batting, or fielding. The slugging percentage is a key metric in the game.
The baseball slugging percentage or SLG measures the number of bases a player achieves with each at bat. It measures the player’s proficiency at hitting the extra-base hits such as doubles, triples, and home runs, and any SLG over .450 is considered good, and .550 or better is exceptional.
Let’s get gloved up and ready to bat as we look at the SLG in detail and understand how it’s calculated, do some actual examples of SLG calculations, and explore what a good SLG in baseball is and a little history of the baseball slugging percentage.
How To Calculate The Baseball Slugging Percentage
To calculate the SLG, you take the total number of bases divided by the total number of at-bats. To get the total number of bases for the equation, you take the player’s total hits and add one base for every double, two for every triple, and three for every home run.
The SLG formula is as follows : [1B + (2B x 2) + (3B x 3) + (HRx4)]/AB.
Remember that the term ‘at-bat’ is defined as a batter getting a hit and reaches by an error or fielder’s choice or is on a ‘non-sacrifice put-out.’ Walks, sacrifice flies, sacrifice bunts, and hit-by-pitch are not included on the SLG stats, and these are categorized under the ‘plate appearance’ stats.
What Is a Good Baseball Slugging Percentage?
Any SLG which is .350 or worse is considered poor, .450 or higher is considered good, while .550 is rated as excellent, and above .650 is regarded as an SLG in the elite category. To give you an indication of SLG over the last 17 years, from 2005, every player that has led SLG in the American and National League had an LSG between .551 and .671, and during that same time, only 119 players posted an SLG of .350 or less.
To demonstrate the difficulty in achieving the elite level of .650 in SLG in a single season, since 2005, only eight players have done this and topped this mark. Each of those hitters blasted a minimum of 37 home runs with a batting average of .300 or better.
Conversely, on the lower end of this scale, only fifteen of the 119 players that posted an SLG of .350 since 2005 hit ten home runs, none of them hit 16 home runs or more, and none had a batting average of .252 or better either.
The exception in this group is Louis Castillo, who was the only player to bat over .300 with a .302 batting average achieved in 2009, and this is largely due to his low number of 16 extra base hits over the whole season.
Top Ten Baseball Slugging Percentages Of All Time
Now, for even more context, let’s look at the top ten baseball slugging percentage leaders of all time:
- 10 – Joe Di Maggio – .5788
- 9 – Mike Trout – .5821
- 8 – Manny Ramirez – .5854
- 7 – Mark McGwire – .5882
- 6 – Hank Greenberg – .6050
- 5 – Barry Bonds – .6069
- 4 – Jimmie Foxx – .6093
- 3 – Lou Gehrig – .6324
- 2 – Ted Williams – 0.6338
- 1 – Babe Ruth – 0.6897
Only Babe Ruth in this elite list topped the .0650 SLG average and by some margin, which shows this baseball legend’s incredible hitting ability!
In 2001, Barry Bonds set the record SLG in a season with a mind-blowing average of .863, including 73 home runs with 411 bases in 476 at-bats, and this included a season batting average of .328!
This eclipsed Babe Ruth’s previous record of .847 set in 1920, and these two players are the only two to have topped .800 SLG in a season, and they have each done it twice! They also share the top six SLG stats for a single season, each with three of those seasons to their name.
As far as team SLG records go, the 2019 Houston Astros held a collective SLG of .495, hitting 288 home runs, and in that same year, the New York Yankees and The Minnesota Twins each posted SLG averages of .490 and .494, respectively, which were the fourth and second-highest in MLB history.
Because the baseball slugging percentage takes more than just home runs into account, it is one of the best measures of power for hitters in baseball. The SLG can even be used for evaluating pitchers; this is known as the ‘slugging percentage against’ but is not used very often.
A Brief History Of The Baseball Slugging Percentage
The ‘total bases average’ was the SLG’s predecessor and was invented in 1867 by Henry Chadwick. This stat measured the number of bases a player achieved in a game. It took about sixty years (1923) before the modern SLG was used in the National League and nearly 80 years (1946) before it was adopted into the American League.
Chadwick believed that the existing system of hits achieved in a game by a batter did not truly reflect the player’s effectiveness as fielding errors of the time (due to the lack of gloves used by the fielding team) meant that a batter hitting single could reach third base due to fielding errors.
The SLG only became commonplace on the back of baseball cards in 1981, while the first appearance of this stat was on Ralph Kiner’s card in 1952. Today, SLG is a stat embedded in the game and quickly tells whether the player is a slap hitter or slugger to be feared!
Conclusion
The baseball slugging percentage is an effective metric that gives players, pitchers, coaches, and fans alike an immediate measure of the hitting power of their favorite batters and an expectation of what to expect when those players are at the plate.
Using this metric adds deeper insight and appreciation for the batting skills and power of hitters. Now that you know that little bit more about it, it will certainly bring you a better understanding of the player’s batting ability in America’s favorite game.