Here in the FanGraphs Library, we have many pages devoted to extremely detailed breakdowns of some of our most prominent statistics. You can find hundreds of words about Weighted On-Base Average (wOBA) or Batting Average on Balls in Play (BABIP) for instance, but sometimes you aren’t looking for hundreds of words. Sometimes you just want some very basic information.

With that in mind, we present this post which will serve as a *complete *directory for every single pitching statistic available at FanGraphs. This post is organized in accordance with our leaderboards, so if you see something in the “Advanced” tab of the leaderboard that you don’t recognize, come to this page and find the matching acronym in the “Advanced” section. You can also use “CTRL + F” in most browsers and type in the stat you’re looking to identify.

There are a few stray statistics located around the site that don’t show up on the leaderboards, so please let us know if you find something that needs to be added. In any of the cases in which we have a full post about the stat, you’ll find links to that page.

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### Dashboard

W (Wins): Number of wins.

L (Losses): Number of losses.

SV (Saves): Number of saves.

G (Games): Number of games in which the pitcher appeared.

GS (Games Started): Number of games the pitcher started.

IP (Innings Pitched): Number of total innings pitched (.1 represents 1/3 of an inning, .2 represents 2/3 of an inning).

K/9 (Strikeouts per 9 innings): Average number of strikeouts per 9 innings.

BB/9 (Walks per 9 innings): Average number of walks per 9 innings.

HR/9 (Home Runs per 9 innings): Average number of home runs allowed per 9 innings.

BABIP (Batting Average on Balls in Play): The rate at which the pitcher allows a hit when the ball is put in play, calculated as (H-HR)/(AB-K-HR+SF).

LOB% (Left On-Base Percentage): Percentage of pitcher’s own base runners that they strand over the course of a season. Not equal to the LOB column in the box score.

GB% (Ground Ball Percentage): The percentage of a pitcher’s balls in play that are ground balls, calculated as GB/BIP.

HR/FB (Home Run to Fly Ball Rate): Percentage of a pitcher’s fly balls that go for home runs, calculated as HB/FB (even though some HR are line drives).

ERA (Earned Run Average): The average number of earned runs a pitcher allows per 9 innings. ((ER*9)/IP)

FIP (Fielding Independent Pitching): An estimate of a pitcher’s ERA based on strikeouts, walks/HBP, and home runs allowed, assuming league average results on balls in play.

xFIP (Expected Fielding Independent Pitching): An estimate of a pitcher’s ERA based on strikeouts, walks/HBP, and fly balls allowed, assuming league average results on balls in play and home run to fly ball ratio.

WAR (Wins Above Replacement): A comprehensive statistic that estimates the number of wins a player has been worth to his team compared to a freely available player such as a minor league free agent based on FIP.

### Standard:

W (Wins): Number of wins.

L (Losses): Number of losses.

ERA (Earned Run Average): The average number of earned runs a pitcher allows per 9 innings. ((ER*9)/IP)

G (Games): Number of games in which the pitcher appeared.

GS (Games Started): Number of games the pitcher started.

CG (Complete Games): Number of starts in which the pitcher recorded every out of an official game.

ShO (Shutouts): Number of complete games in which the pitcher allowed no runs.

SV (Saves): Number of saves.

HLD (Holds): Number of holds.

BS (Blown Saves): Number of times the pitcher entered in a save situation as lost the lead.

IP (Innings Pitched): Number of total innings pitched (.1 represents 1/3 of an inning, .2 represents 2/3 of an inning).

TBF (Total Batters Faced): The number of batters a pitcher has faced, akin to plate appearances.

H (Hits Allowed): Number of hits allowed by the pitcher.

R (Runs Allowed): Number of runs allowed by the pitcher.

ER (Earned Runs Allowed): Number of earned runs allowed by the pitcher, determined by the official scorer.

BB (Walks): Number of walks allowed by the pitcher.

IBB (Intentional Walks): Number of intentional walks issue by the pitcher.

HBP (Hit By Pitches): Number of hit batters.

WP (Wild Pitches): Number of wild pitches.

BK (Balks): Number of balks.

SO (Strikeouts): Number of strikeouts.

### Advanced:

K/9 (Strikeouts per 9 innings): Average number of strikeouts per 9 innings.

BB/9 (Walks per 9 innings): Average number of walks per 9 innings.

K/BB (Strikeout to Walk Ratio): Strikeouts divided by walks.

HR/9 (Home Runs per 9 innings): Average number of home runs allowed per 9 innings.

K% (Strikeout Percentage): Frequency with which the pitcher has struck out a batter, calculated as strikeouts divided by total batters faced.

BB% (Walk Percentage): Frequency with which the pitcher has issued a walk, calculated as walks divided by total batters faced.

K%-BB% (Strikeout Percentage minus Walk Percentage): The percentage differential between K% and BB%, often a better indicator of performance than K/BB, which can be skewed by very low walk rates.

AVG (Batting Average Against): Rate of hits allowed per at bat, calculated as H/AB.

WHIP (Walks Plus Hits per Inning Pitched): The average number of base runners allowed via hit or walk per inning.

BABIP (Batting Average on Balls in Play): The rate at which the pitcher allows a hit when the ball is put in play, calculated as (H-HR)/(AB-K-HR+SF).

LOB% (Left On-Base Percentage): Percentage of pitcher’s own base runners that they strand over the course of a season. Not equal to the LOB column in the box score.

ERA- (Earned Run Average minus): ERA adjusted for park effects and league average (set to 100 for each year).

FIP- (Fielding Independent Pitching minus): FIP adjusted for park effects and league average (set to 100 for each year).

xFIP (Expected Fielding Independent Pitching minus): xFIP adjusted for park effects and league average (set to 100 for each year).

ERA (Earned Run Average): The average number of earned runs a pitcher allows per 9 innings. ((ER*9)/IP)

FIP (Fielding Independent Pitching): An estimate of a pitcher’s ERA based on strikeouts, walks/HBP, and home runs allowed, assuming league average results on balls in play.

E-F (ERA-FIP Differential): The difference between the pitcher’s ERA and FIP.

xFIP (Expected Fielding Independent Pitching): An estimate of a pitcher’s ERA based on strikeouts, walks/HBP, and fly balls allowed, assuming league average results on balls in play and home run to fly ball ratio.

SIERA (Skill Interactive ERA): An ERA estimator that attempts to more accurately capture a pitcher’s performance based on strikeouts, walks/HBP, home runs, and batted ball data.

### Batted Ball

BABIP (Batting Average on Balls in Play): The rate at which the pitcher allows a hit when the ball in put play, calculated as (H-HR)/(AB-K-HR+SF).

GB/FB (Ground Ball to Fly Ball Ratio): The ratio of ground balls a pitcher allows to fly balls, calculated as GB/FB.

LD% (Line Drive Percentage): The percentage of a pitchers’s balls in play that are line drives, calculated as LD/BIP.

GB% (Ground Ball Percentage): The percentage of a pitchers’s balls in play that are ground balls, calculated as GB/BIP.

FB% (Fly Ball Percentage): The percentage of a pitcherss balls in play that are fly balls, calculated as FB/BIP.

IFFB% (Infield Fly Ball Percentage): Percentage of a pitchers’s fly balls that were infield fly balls, calculated as IFFB/FB.

HR/FB (Home Run to Fly Ball Rate): Percentage of a pitcher’s fly balls that go for home runs, calculated as HB/FB (even though some HR are line drives).

RS (Run Support): Number of runs the pitcher’s team has scored during their appearances.

RS/9 (Run Support per 9 innings): Number of runs the pitcher’s team has scored during their appearances per 9 innings.

Balls (Balls): Number of total balls thrown.

Strikes (Strikes): Number of total strikes thrown.

Pitches (Pitches): Number of total pitches thrown.

Pull% (Pull Percentage): Percentage of batted balls hit to the pull field.

Cent% (Center Percentage): Percentage of batted balls hit to the middle of the field.

Oppo% (Opposite Field Percentage): Percentage of batted balls hit to the opposite field.

Soft% (Soft Contact Percentage): Percentage of soft-hit batted balls.

Med% (Medium Contact Percentage): Percentage of medium-hit batted balls.

Hard% (Hard Contact Percentage): Percentage of hard-hit batted balls.

### Win Probability

WPA (Win Probability Added): The total impact a pitcher’s batters faced (or SB/CS) have on his team’s win expectancy relative to league average.

-WPA (Negative Win Probability Added): The sum of a pitcher’s negative WPA events.

+WPA (Positive Win Probability Added): The sum of a pitcher’s positive WPA events.

RE24 (Run Expectancy 24 Base Out State): The total impact a pitcher’s batters faced (or SB/CS) have on his team’s run expectancy relative to league average.

REW (Run Expectancy Wins): RE24 converted from runs to wins.

pLI (Average Leverage Index): The average leverage index of each pitcher’s batters faced.

inLI (Inning Leverage Index): The average leverage index at the beginning of the inning for the pitcher.

gmLI (Game Leverage Index): The average leverage index at the beginning of the game for the pitcher.

exLI (Exit Leverage Index): The average leverage index at the end of the appearance for the pitcher.

Pulls (Pulls): Number of times the pitcher has been removed from a game.

WPA/LI (Situational Wins): A player’s WPA controlling for leverage index, calculated as the sum of each event’s WPA/LI, not total WPA/LI.

Clutch (Clutch Score): The difference between a player’s totalWPA/pLI and their WPA/LI defined above.

SD (Shutdowns): Number of relief appearances worth 0.06 WPA or more.

MD (Meltdowns): Number of relief appearances worth -0.06 or less.

### Pitch Type

*This section refers to data from Baseball Info Solutions. Raw PITCHf/x data is found in the PITCHf/x section. The % numbers refer to percentage and the “v” numbers refer to average velocity.*

FB% (Fastball Percentage)

FBv (Average Fastball Velocity)

SL% (Slider Percentage)

SLv (Average Slider Velocity)

CT% (Cutter Percentage)

CTv (Average Cutter Velocity)

CB% (Curveball Percentage)

CBv (Average Curveball Velocity)

CH% (Changeup Percentage)

CHv (Average Changeup Velocity)

SF% (Split-Finger Percentage)

SFv (Average Split-Finger Velocity)

KN% (Knuckleball Percentage)

KNv (Average Knuckleball Velocity)

XX% (Unidentified Pitch Percentage)

### Pitch Value

*This section refers to pitch data from Baseball Info Solutions and denotes the number of runs above average a batter was against a specific pitch type (or that type per 100 pitches). Learn more about them here.*

wFB (Weighted Fastball Runs)

wSL (Weighted Slider Runs)

wCT (Weighted Cutter Runs)

wCH (Weighted Changeup Runs)

wSF (Weighted Split Finger Runs)

wKN (Weighted Knuckleball Runs)

wFB/C (Weighted Fastball Runs per 100 pitches)

wSL/C (Weighted Slider Runs per 100 pitches)

wCT/C (Weighted Cutter Runs per 100 pitches)

wCH/C (Weighted Changeup Runs per 100 pitches)

wSF/C (Weighted Split Finger per 100 pitches)

wKN/C (Weighted Knuckleball Runs per 100 pitches)

### Plate Discipline

*These statistics are based on data from Baseball Info Solutions. Learn more about them here.*

O-Swing% (Outside the Zone Swing Percentage): Swings at pitches outside the zone divided by pitches outside the zone.

Z-Swing% (Inside the Zone Swing Percentage): Swings at pitches inside the zone divided by pitches inside the zone.

Swing% (Swing Percentage): Swings divided by total pitches.

O-Contact% (Outside the Zone Contact Percentage): Contact made outside the zone divided by swings outside the zone.

Z-Contact% (Inside the Zone Contact Percentage): Contact made inside the zone divided by swings inside the zone.

Contact% (Contact Percentage): Contact made divided by swings.

Zone% (Zone Percentage): Pitches inside the zone divided by total pitches.

F-Strike% (First Pitch Strike Percentage): Percentage of PA that begin with a strike.

SwStr% (Swinging Strike Percentage): Swinging strikes divided by total pitches.

### Value

*Note: The pitcher WAR section of the Library is still in need of revision!*

RA9-WAR (Runs Allowed based WAR): A comprehensive statistic that estimates the number of wins a player has been worth to his team compared to a freely available player such as a minor league free agent based on his runs allowed per 9.

BIP-Wins (BABIP Wins): An estimate of how many wins a pitcher has added by having a BABIP above or below league average. It adjusts for park and league.

LOB-Wins (Left On-Base Wins): An estimate of how many wins a pitcher has added as a result of stranding runners on base.

FDP-Wins (Fielding Dependent Wins): The sum of BIP-Wins and LOB-Wins. It is also the difference between RA9-Wins and FanGraphs’ standard FIP-based pitching WAR.

RAR (Runs Above Replacement): The number of runs a player has been worth to his team compared to a freely available player based on FIP.

WAR (Wins Above Replacement): A comprehensive statistic that estimates the number of wins a player has been worth to his team compared to a freely available player such as a minor league free agent based on his FIP.

Dollars (Dollar Value of Performance): The amount of money a player’s production would be worth on the free agent market in millions of dollars. This column uses $5.5MM/WAR, but that is a calculation from several years ago. The current number is between $6 million and $7 million.

### PITCHf/x Pitch Type

*The following represent pitch type percentages according to PITCHf/x data. The name of the pitch is next to each. *

FA% (Four Seam and Unclassified Fastballs)

FT% (Two Seam Fastballs)

FC% (Cutters)

FS% (Split Fingers)

FO% (Forkballs)

SI% (Sinkers)

SL% (Sliders)

CU% (Cuvreballs)

KC% (Knuckle-Curves)

EP% (Ephesuses)

CH% (Changeups)

SC% (Screwballs)

KN% (Knuckleballs)

UN% (Unknowns)

### PITCHf/x Velocity

*The following are the average velocities according to PITCHf/x data. The name of the pitch is next to each.*

vFA (Four Seam and Unclassified Fastballs)

vFT (Two Seam Fastballs)

vFC (Cutters)

vFS (Split Fingers)

vFO (Forkballs)

vSI (Sinkers)

vSL (Sliders)

vCU (Cuvreballs)

vKC (Knuckle-Curves)

vEP (Ephesuses)

vCH (Changeups)

vSC (Screwballs)

vKN (Knuckleballs)

vUN (Unknowns)

### PITCHf/x H-Movement

*The following are the average horizontal movements of the pitches according to PITCHf/x. The name of the pitch is next to each. (Negative values move toward RHH, positive values move toward LHH)*

FA-X (Four Seam and Unclassified Fastballs)

FT-X (Two Seam Fastballs)

FC-X (Cutters)

FS-X (Split Fingers)

FO-X (Forkballs)

SI-X (Sinkers)

SL-X (Sliders)

CU-X (Cuvreballs)

KC-X (Knuckle-Curves)

EP-X (Ephesuses)

CH-X (Changeups)

SC-X (Screwballs)

KN-X (Knuckleballs)

UN-X (Unknowns)

### PITCHf/x V-Movement

*The following are the average vertical movements of the pitches according to PITCHf/x. The name of the pitch is next to each. (Numbers are relative to a pitch with no spin, meaning gravity’s effect is removed)*

FA-Z (Four Seam and Unclassified Fastballs)

FT-Z (Two Seam Fastballs)

FC-Z (Cutters)

FS-Z (Split Fingers)

FO-Z (Forkballs)

SI-Z (Sinkers)

SL-Z (Sliders)

CU-Z (Cuvreballs)

KC-Z (Knuckle-Curves)

EP-Z (Ephesuses)

CH-Z (Changeups)

SC-Z (Screwballs)

KN-Z (Knuckleballs)

UN-Z (Unknowns)

### PITCHf/x Pitch Type Value

*The following are runs above average against each pitch using PITCHf/x data. The name of the pitch is next to each. Learn about pitch values here.*

wFA (Four Seam and Unclassified Fastballs)

wFT (Two Seam Fastballs)

wFC (Cutters)

wFS (Split Fingers)

wFO (Forkballs)

wSI (Sinkers)

wSL (Sliders)

wCU (Cuvreballs)

wKC (Knuckle-Curves)

wEP (Ephesuses)

wCH (Changeups)

wSC (Screwballs)

wKN (Knuckleballs)

wUN (Unknowns)

### PITCHf/x Pitch Value/100

*The following are runs above average against each pitch per 100 pitches using PITCHf/x data. The name of the pitch is next to each. Learn about pitch values here.*

wFA/C (Four Seam and Unclassified Fastballs)

wFT/C (Two Seam Fastballs)

wFC/C (Cutters)

wFS/C (Split Fingers)

wFO/C (Forkballs)

wSI/C (Sinkers)

wSL/C (Sliders)

wCU/C (Cuvreballs)

wKC/C (Knuckle-Curves)

wEP/C (Ephesuses)

wCH/C (Changeups)

wSC/C (Screwballs)

wKN/C (Knuckleballs)

wUN/C (Unknowns)

### PITCHf/x Plate Discipline

*The following are plate discipline numbers using PITCHf/x data. Learn about plate discipline numbers here.*

IP (Innings Pitched): Number of total innings pitched (.1 represents 1/3 of an inning, .2 represents 2/3 of an inning).

O-Swing% (Outside the Zone Swing Percentage): Swings at pitches outside the zone divided by pitches outside the zone.

Z-Swing% (Inside the Zone Swing Percentage): Swings at pitches inside the zone divided by pitches inside the zone.

Swing% (Swing Percentage): Swings divided by total pitches.

O-Contact% (Outside the Zone Contact Percentage): Contact made outside the zone divided by swings outside the zone.

Z-Contact% (Inside the Zone Contact Percentage): Contact made inside the zone divided by swings inside the zone.

Contact% (Contact Percentage): Contact made divided by swings.

Zone% (Zone Percentage): Pitches inside the zone divided by total pitches.

Pace (Average Time Between Pitches): Average time between pitches seen by a batter, based on PITCHf/x timestamps.

### Other

GSv2 (Game Score Version 2.0): FanGraphs’ version of Game Score, which rates starts based on outs, strikeouts, walks, hits, and home runs.