Hey, just so you know, some of the links on this site are affiliate links. That means I may earn a small commission if you buy something through them. It doesn’t cost you anything extra, and it helps me keep this site running. Thanks for your support!
If you are new to baseball, you do not need to learn every statistic at once. Start with a small group that explains how often hitters reach base, how much damage they do, and how effectively pitchers prevent runs and baserunners.
This guide focuses on the numbers that appear most often in broadcasts, scoreboards and player pages.
Batting average (AVG)
Batting average is hits divided by official at-bats. A .300 average means three hits per 10 official at-bats.
It is intuitive, but limited. MLB’s glossary notes that batting average does not include walks or hit-by-pitches and treats singles and home runs equally as “hits.”
On-base percentage (OBP)
OBP measures how often a batter reaches base through hits, walks and hit-by-pitches, with specific denominator adjustments under the official formula.
For beginners, the concept matters more than memorizing the formula: OBP asks how often the hitter avoids making an out.
Slugging percentage (SLG)
Slugging percentage weights hits by total bases. A double counts more than a single; a home run counts more than a double.
That makes SLG a simple power-oriented complement to batting average.
OPS
OPS adds OBP and SLG together. MLB describes it as a way to combine reaching base with hitting for power.
It is not a perfect all-in-one hitting stat, but it is much more informative than batting average alone.
Slash line
When you see something like .285/.370/.510, that is a slash line:
- batting average;
- on-base percentage;
- slugging percentage.
Those three numbers quickly summarize a hitter’s traditional rate-stat profile.
Home runs (HR) and runs batted in (RBI)
Home runs are easy to understand: the batter circles all bases and scores. RBI counts runs driven in by the batter under scoring rules.
RBI can be influenced by opportunity because hitters need teammates on base to drive them in. It is useful context, but not a pure individual-skill measure.
Stolen bases (SB)
Stolen bases track successful advances without a batted ball or defensive error being the primary cause. The total is more useful when paired with caught-stealing information because efficiency matters.
Earned run average (ERA)
ERA estimates how many earned runs a pitcher allows per nine innings.
It is one of baseball’s oldest pitching standards, but defense, ballpark and sequencing can influence the result.
WHIP
WHIP stands for walks plus hits per inning pitched. It focuses on how many baserunners a pitcher allows through those two routes.
A lower WHIP generally means fewer runners are reaching against the pitcher.
Strikeouts (K) and walks (BB)
Strikeouts remove the chance that a batted ball becomes a hit. Walks give the opponent a free baserunner. That makes strikeout and walk rates especially useful for understanding what a pitcher directly controls.
Wins, losses and saves
Pitcher wins and losses remain part of baseball vocabulary, but they depend heavily on team scoring, bullpen support and timing. Saves measure certain late-game relief situations under official scoring rules.
Use them as part of a larger picture rather than as stand-alone proof of pitcher quality.
OPS+
OPS+ adjusts OPS for league and ballpark context and scales league average to 100. MLB’s glossary explains that 150 means 50% better than league average under the metric.
This is a good first step into adjusted statistics because the scale is easy to read.
WAR comes later
Wins Above Replacement attempts to combine a player’s total value into one estimate. It is useful, but it has multiple implementations. Read WAR in Baseball Explained after you are comfortable with the basic stats.
Beginner cheat sheet
| Stat | Question it answers |
|---|---|
| AVG | How often does he get a hit in an at-bat? |
| OBP | How often does he reach base? |
| SLG | How much total-base power does he produce? |
| OPS | How well does he combine reaching base and power? |
| ERA | How many earned runs does the pitcher allow per nine? |
| WHIP | How many walks and hits does he allow per inning? |
Official references
Bottom line
Learn AVG, OBP, SLG, OPS, ERA and WHIP first. Once those become familiar, advanced statistics make much more sense because you already understand the questions they are trying to improve.
