Baseball Stats 101: A Complete Glossary of Baseball Statistics


Stats

During one of our baseball games, I was keeping track of the game in our scorebook. After a while, one of my teammates started talking about how many different stats there are in baseball and that got me wondering – how many stats are there in baseball? I knew there were a lot of stats, but it surprised me to find out just how many stats there are in baseball.

In total, there are 121 statistics in baseball. Of those 121 statistics, 72 baseball statistics are considered “standard” while 49 baseball statistics are considered “advanced”.

In addition to the standard and advanced stats, there are another 32 statistics that the MLB labels as “Statcast”. These cover things like Arm Strength (ARM), Catcher Framing, and Launch Angle (LA). This article does not cover those Statcast statistics, but if you’re interested in learning more you can head over to the Statcast section at MLB.

A Complete List of Baseball Statistics

Courtesy of the MLB, I was able to find what is considered to be a standard baseball statistic and an advanced baseball statistic. The lists below are a complete glossary of all of the statistics in baseball and these lists are split up into two sections – the “Standard Baseball Statistics” section and the “Advanced Baseball Statistics” section.

A Complete Glossary of Baseball Statistics

Standard Batting Stats

At-bat (AB)

  • Any plate appearance that ends with the batter getting out (except for sacrifice plays)
  • Any plate appearance that ends with the batter safely reaching base via a hit, error, or fielder’s choice
  • An at-bat is not counted if the plate appearance results in a sacrifice play, walk, hit by pitch, or catcher’s interference
  • Learn more about what is an At-Bat in baseball

Batting Average (AVG)

  • The total number of hits divided by the total number of at-bats

Caught Stealing (CS)

  • A base runner is thrown out in-between pitches
    • A base runner is thrown out while attempting to steal second, third, or home
    • A base runner is picked-off by the pitcher
    • A base runner is picked-off by the catcher

Double (2B)

  • A batter puts the ball in play and safely reaches second base without the help of a defensive error or a fielder’s choice

Extra-base Hit (XBH)

  • A base hit that results in a double, triple, or home run

Games Played (G)

  • A game played is counted whenever a player enters the game at any point

Grand Slam (GSH)

  • A home run with base runners on first, second, and third base

Ground Into Double Play (GIDP)

  • A batter hits a ground ball that results in any type of double play

Groundout-to-Airout Ratio (GO/AO)

  • A single number that compares how often a batter gets out by hitting a ground ball or by hitting a fly ball
  • Calculated by: (number of ground outs / number of flyouts)

Hit-by-pitch (HBP)

  • A batter is hit by a pitch and is awarded first base

Hit (H)

  • A batter puts the ball in play and safely makes it to at least first base without the assistance of an error or a fielder’s choice play

Home Run (HR)

  • A batter puts the ball in play and safely makes it around all four bases without the assistance of an error or a fielder’s choice play

Intentional Walk (IBB)

  • The defensive team purposely walks a batter

Left On Base (LOB)

  • The number of base runners who were left on base at the end of an inning

On-base Percentage (OBP)

  • The total number of hits, walks, and hit-by-pitches divided by the total number of plate appearances
  • On-base percentage, formatted as 0.000, is a number that indicates how often a player safely reaches base

On-base Plus Slugging (OPS)

  • This number, formatted as .0000, is a number that indicates how well a hitter can safely reach base and hit for power
  • Calculated by adding the on-base percentage and the slugging average

Plate Appearance (PA)

  • The total number of times a player completes a batting turn

Reached On Error (ROE)

  • A batter safely makes it to base because of a defensive error

Run (R)

  • A base runner safely touches home plate

Runs Batted In (RBI)

  • A batter is awarded an RBI for each runner that safely crosses home plate when they put the ball in play
  • A Run Batted In is not counted if a runner scores when the batter hits into a double play or if there was a defensive error that caused the runner to score

Sacrifice Bunt / Sacrifice Hit (SH)

  • A batter advances the baserunner by bunting the ball, but getting thrown out at first base
  • A batter can also be credited with a sacrifice bunt if they safely reach first base on a fielder’s choice or an error and the base runner still advances.

Sacrifice Fly (SF)

  • A batter hits a fly ball out, which leads to a base runner scoring a run

Single (1B)

  • A batter puts the ball in play and safely reaches first base without the help of a defensive error or a fielder’s choice

Slugging Percentage (SLG)

  • A number, formatted as 0.000, that indicates how well a player hits for extra base hits
  • Formula for slugging percentage: (1B + 2(2B) + 3(3B) + 4(4B)) / At-Bats

Stolen Base (SB)

  • A base runner safely reaches the next base without the batter putting the ball in play and without the assistance of a defensive error

Stolen-base Percentage (SB%)

  • The number of successful stolen bases divided by the number of stolen base attempts

Total Bases (TB)

  • The number of bases a batter earns because of their base hits:
    • Single (1), Double (2), Triple (3), Home Run (4)

Triple (3B)

  • A batter puts the ball in play and safely reaches third base without the help of a defensive error or a fielder’s choice

Walk (BB)

  • A Walk, also called Base on Balls, is when a batter receives four balls in one plate appearance and is awarded first base

Walk-off (WO)

  • The home team scores the winning run in the bottom of the last inning

Standard Fielding Stats

Assist (A)

  • Awarded to a defensive player who touches the ball (intentionally or unintentionally) prior to a base runner being thrown out
    • Example: A shortstop is credited with an assist when they field a ground ball and throw the runner out at first base

Caught Stealing Percentage (CS%)

  • The number of times a catcher throws out a base runner divided by the number of times base runners attempt to steal a base on that catcher

Double Play (DP)

  • Any play where two offensive players are called out during the same play

Error (E)

  • A defensive player fails to successfully make a play that an average fielder should be able to make

Fielding Percentage (FPCT)

  • The number of putouts and assists of a defensive player divided by the total number of chances they had to make an out

Innings Played (INN)

  • The total number of defensive outs played divided by 3

Out (O)

  • One out is recorded when an offensive player is retired by the defense
  • Each team gets 3 outs per half-inning

Outfield Assist (OFA)

  • An outfielder throws the ball into the infield and an out is recorded because of that throw

Passed Ball (PB)

  • When a catcher misses a pitch they should have caught and at least one runner advances a base
  • A Passed Ball is not considered an error

Putout (PO)

  • The fielder who is holding the ball when an out is made is credited with a putout

Total Chances (TC)

  • The number of times a fielder has a chance of recording an out
  • Calculated as assists + putouts + errors

Triple Play (TP)

  • Any play where three offensive players are called out during the same play

Standard Pitching Stats

Appearance (App)

  • The number of times a pitcher enters a game

Balk (BK)

Batters Faced (BF)

  • The number of plate appearances a pitcher faced

Blown Save (BS)

  • A pitcher comes into the game during a Save Opportunity, but the opposing team scores the tying run

Complete Game (CG)

  • A pitcher throws to every batter in a single game, regardless of how long the game lasts

Earned Run (ER)

  • A base runner scores without the assist of an error or passed ball

Earned Run Average (ERA)

  • The average number of earned runs per nine innings (seven innings for high school)
  • Calculated as: 9 x (Earned Runs / Innings Pitched)

Flyout

  • Sometimes abbreviated as “F”, a fly ball is when a batter hits a ball into the air and it gets caught before touching the ground
  • Line drives do not count as a Fly Out

Games Finished (GF)

  • A relief pitcher who was the final pitcher of the game for their team

Games Started (GS)

  • The player who threw the first pitch of the game for their team

Groundout

  • Sometimes abbreviated as “G”, a groundout is when a player hits the ball on the ground and is either thrown out at first base or gets on because of a fielder’s choice

Hold (HLD)

  • A pitcher comes into the game during a Save Opportunity and records at least one out before being relieved by the next pitcher

Inherited Runner (IR)

  • The number of baserunners who are already on base when a pitcher enters the game

Innings Pitched (IP)

  • The numbers of innings a pitcher throws, measured in thirds (one out equals one third)

Loss (L)

  • The pitcher who is credited with the earned run when the opposing team takes the final lead of the game

Number of Pitches (NP)

  • The total number of pitches a pitcher throws

Pickoff (PK)

  • In between pitches, a pitcher throws the ball to a defensive player, who tags out a base runner

Quality Start (QS)

  • A starting pitcher who throws a minimum of six innings and gives up three earned runs or fewer

Relief Win (RW)

  • A relief pitcher who is credited with the win

Save (SV)

  • Credited to the final relief pitcher for the winning team who entered the game during a Save Opportunity

Save Opportunity (SVO)

  • The final relief pitcher for the winning team, who is not the winning pitcher, throws at least ⅓ of an inning and one of the following conditions are true:
    • Pitch at least one inning when their team is winning by no more than three runs
    • Enters the game with the tying run on base, up to bat, or on deck
    • Pitches for at least three innings

Save Percentage (SV%)

  • A pitcher’s total saves divided by that pitcher’s total Save Opportunities 

Shutout (SHO)

Strikeout (SO, K)

  • Three strikes are charged to a batter during one at-bat

Unearned Run (UER)

  • A run that scores because of a defensive error or a passed ball

Walks And Hits Per Inning Pitched (WHIP)

  • Formula: (Walks + Hits) / Innings Pitched
  • The lower the number, the better a pitcher is at preventing runners from reaching base

Wild Pitch (WP)

  • A pitch so far out of the strike zone that a catcher is unable to catch it and at least one baserunner advances

Win (W)

  • Awarded to the pitcher who was in the game when their team took the lead for good
  • For a starting pitcher to be awarded a win, they must also pitch for a minimum of five innings (for a standard nine inning game) 

Winning Percentage (WPCT)

  • The number of wins divided by the number of decisions (wins + losses)

Standard Team Stats

Run Differential

  • The total number of runs a team has allowed minus the total number of runs the team has scored

Advanced Baseball Stats

Advanced Batting Stats

Batting Average on Balls in Play (BABIP)

  • A batter’s average for balls that are put in play (excludes strikeouts, home runs, and sacrifice flies)
  • Formula: (Hits – Home Runs) / (At-Bats – Strikeouts – Home Runs – Sacrifice Flies)

Isolated Power (ISO)

  • Only takes into account extra base-hits and is an indicator of how often a player hits for extra bases
  • Formula: ((1 x Double) + (2 x Triple) + (3 X Home Run)) / At-Bats

Late-inning Pressure Situation (LIPS)

  • When a batter has an at-bat in the seventh inning or later and one of the following scenarios is true:
    • The batter’s team is losing by three or fewer runs
    • The batter’s team is tied
    • The batter’s team is leading by one run
    • The bases are loaded and the batter’s team is losing by four runs

On-base Plus Slugging Plus (OPS+)

  • A number used to normalize a player’s On Base Percentage across all batters in the league, while accounting for small external variables (like ballparks)
  • Formula: (On Base Percentage  / League On Base Percentage) * 100
  • Learn more about On-base Plus Slugging Plus statistic

Pitches Per Plate Appearance (P/PA)

  • The number of pitches thrown per Plate Appearance

Plate Appearances Per Strikeout (PA/SO)

  • Total Plate Appearances divided by the total number of Strikeouts

Runs Created (RC)

  • Shows how offensive a player contributed to a team
  • Formula: (Total Bases * (Hits + Walks)) / (At-Bats + Walks)

Weighted Runs Above Average (wRAA)

  • A measure of how many runs a player contributes, compared with the league average
  • Formula: ((wOBA – wOBA of league) / annual wOBA scale) * Plate Appearances
  • Learn more about Weighted Runs Above Average

Weighted On-base Average (wOBA)

  • Another version of the On-base Percentage, but it also gives a weighted factor to extra base hits (for example: a triple is worth more than a double)
  • Learn more about Weighted On-base Average

Weighted Runs Created Plus (wRC+)

  • Uses the Run Created stat and normalizes it across the entire league, adjusting for external factors (like ballpark)
  • Learn more about Weighted Runs Created Plus

Win Probability Added (WPA)

  • The total change in percentage a team has to win the game after any event
    • For example, if a team’s percentage of winning moves from 40 percent to 60 percent after one event, the WPA is .20
  • Learn more about Win Probability Added

Wins Above Replacement (WAR)

  • A measurement, in terms of wins, of how valuable one player is over another player who could replace them at the same position
  • Learn more about Wins Above Replacement

Advanced Fielding Stats

Defensive Efficiency Ratio (DER)

  • A measurement of how often a team’s defense converts a live ball into an out
  • A higher DER means the defense gets more outs when the ball is put into play

Defensive Runs Saved (DRS)

  • A slightly different measurement than UZR, the DRS is a measurement of how many runs a defensive player saves
  • Learn more about Defensive Runs Saved

Range Factor (RF)

  • An estimate on how much field a player can cover by looking at how many plays a player can make
  • Formula: (Putouts + Assists) / Defensive Games Played

Ultimate Zone Rating (UZR)

  • A slightly different measurement than DRS, the UZR is a measurement of how many runs a defensive player saves
  • Learn more about Ultimate Zone Rating

Advanced Pitching Stats

Adjusted Earned Run Average (ERA+)

  • Uses the Earned Run Average stat and normalizes it across the entire league, adjusting for external factors (like ballpark)
  • Learn more about Adjusted Earned Run Average

Baserunners Per Nine Innings Pitched (MB/9)

  • In a nine inning game, the average number of opponents who reached base via a hit, walk, and hit-by-pitch (errors and fielder’s choice do not count)

Bequeathed Runners (BQR)

  • The number of base runners a pitcher leaves on base when they are replaced by another pitcher

Bequeathed Runners Scored (BQR-S)

  • The total number of Bequeathed Runners (BQR) that score

Expected Fielding Independent Pitching (xFIP)

  • Same measurement as Fielding Independent Pitching (FIP), but it uses an expected home run rate instead of home runs allowed

Fielding Independent Pitching (FIP)

  • Measures the plays the pitcher has the most control over, which are strikeouts, unintentional walks, hit-by-pitches, and home runs

Fly-ball Rate (FB%)

  • The percentage of live balls that are scored as fly balls

Game Score

  • A score between 0 to 100 that tells a story of how well a pitcher is doing.
  • The higher the game score number, the better the pitcher is performing

Ground-ball Rate (GB%)

  • The percentage of live balls that are scored as ground balls

Hits Per Nine Innings (H/9)

  • The average number of hits a pitcher gives up for every nine innings pitched

Home Runs Per Nine Innings (HR/9)

  • The average number of home runs a pitcher gives for every nine innings pitched

Home Run To Fly Ball Rate (HR/FB)

  • The percentage of home runs hit for every fly ball allowed

Inherited Runs Allowed (IR-A)

  • The total number of Inherited Runners (IR) that score on a relief pitcher

Inherited Runs Allowed Percentage (IR-A%)

  • The percentage of Inherited Runners (IR) that score on a relief pitcher

Innings Per Start (I/GS)

  • The average number of innings a pitcher throws when they are the starting pitcher

Leverage Index (LI)

  • A measurement of how significantly a play can impact the win probability of a team
  • Below 1.0 is not very significant, 1.0 is neutral, and above 1.0 is more significant

Line-drive Rate (LD%)

  • The percentage of live balls that are scored as line drives

Pitches Per Inning Pitched (P/IP)

  • The average number of pitches thrown per inning

Pitches Per Start (P/GS)

  • The average number of pitches thrown for a starting pitcher

Pop-up Rate (PO%)

  • The percentage of live balls that are scored as pop-ups

Run Support Per Nine Innings (RS/9)

  • The average amount of runs, per nine innings, that a pitcher’s offense will score while that pitcher is in the game

Runs Allowed Per Nine Innings Pitched (RA9)

  • Total number of runs allowed on average for every nine innings pitched (runs scored because of errors also count)

Skill-interactive Earned Run Average (SIERA)

  • SIERA is a version of Earned Run Average (ERA)
  • SIERA shares some characteristics with Field Independent Pitching (FIP) and Expected Field Independent Pitching (xFIP), but SIERA also takes into account balls in play, which helps answer the question of what makes a pitcher successful
  • Learn more about SIERA

Strikeout Rate (K%)

  • The percentage of Plate Appearances (PA) that are scored as strikeouts (K)

Strikeouts Per Nine Innings (K/9)

  • The average amount of strikeouts a pitcher throws for every nine innings pitched

Strikeout-to-walk Ratio (K/BB)

  • A pitcher’s total strikeouts divided by that pitcher’s total walks

True Earned Run Average (tERA)

  • A version of Earned Run Average (ERA) that also takes into account the type of ball a batter hits (ground ball, fly ball, line drive, pop-up)

Walks Per Nine Innings (BB/9)

  • The average amount of walks a pitcher throws for every nine innings pitched

Walk Rate (BB%)

  • The percentage of Plate Appearances (PA) that are recorded as walks (BB)

Advanced Team Stats

Ballpark Factor

  • A method for how to normalize any statistic across an entire league
  • Used to show how one ballpark favors a pitcher or a hitter

Magic Number (MN)

  • A number needed to reach a certain goal (mainly, making the playoffs) that takes into account how many wins a team needs and how many losses that team needs from their closest competitor
  • Learn more about MLB’s magic number

Pythagorean Winning Percentage

  • Looks at what a team’s record should have been, based on their total number of runs allowed and total number of runs scored

Win Expectancy (WE)

  • The percentage chance a team has to win the game, at any point in the game

Steve Nelson

I'm the owner of Baseball Training World. I live in Denver, Colorado and I enjoy playing baseball on two different adult baseball teams in the surrounding area.

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