Baseball stats glossary: what every abbreviation means

Batting stats

PA: plate appearances

Every completed trip to the plate: at-bats plus walks, hit-by-pitches, sacrifices and catcher's interference.

AB: at-bats

Plate appearances that are not a walk, hit-by-pitch, sacrifice bunt or sacrifice fly.

AVG: batting average

Hits ÷ At-bats. In MLB, .300 is a long-standing mark of a very good hitter. Youth averages vary widely by age and level, so compare within the same league.

OBP: on-base percentage

(Hits + Walks + Hit-by-pitch) ÷ (At-bats + Walks + Hit-by-pitch + Sacrifice flies). How often a batter reaches base.

TB: total bases

Singles + 2×Doubles + 3×Triples + 4×Home runs.

SLG: slugging percentage

Total bases ÷ At-bats. Measures power: how many bases a batter gets per at-bat.

OPS: on-base plus slugging

OBP + SLG. A quick one-number view of a hitter's overall production.

ISO: isolated power

SLG − AVG. Extra-base power, ignoring singles.

BABIP: batting average on balls in play

(Hits − Home runs) ÷ (At-bats − Strikeouts − Home runs + Sacrifice flies).

RBI: runs batted in

Runs that score as a result of the batter's plate appearance.

R: runs scored

Times a player crosses home plate.

BB: walks (bases on balls)

Four balls. Also written BB%, the share of plate appearances that end in a walk.

SO or K: strikeouts

Three strikes. K% is strikeouts ÷ plate appearances.

HBP: hit by pitch

The batter is hit by a pitch and awarded first base.

SH / SF: sacrifice bunt / sacrifice fly

An out that advances or scores a runner. Neither counts as an at-bat.

Pitching stats

IP: innings pitched

Written in thirds: 5.1 is five and one-third innings, 5.2 is five and two-thirds.

ER: earned runs

Runs that scored without the help of an error or passed ball.

ERA: earned run average

(Earned runs × innings in a regulation game) ÷ Innings pitched. Use 9 for nine-inning games; many youth games are six innings, so the multiplier is 6. Compare ERAs only between games of the same length.

WHIP: walks plus hits per inning pitched

(Walks + Hits) ÷ Innings pitched. How many baserunners a pitcher allows per inning.

K/9: strikeouts per nine innings

Strikeouts × 9 ÷ Innings pitched. BB/9 works the same way for walks.

K/BB: strikeout-to-walk ratio

Strikeouts ÷ Walks. A quick read on control.

Pitch count

Total pitches thrown. Many youth leagues set daily limits and required rest by pitch count. See our arm care guide.

W, L, SV, HLD: decisions

Win, loss, save and hold. The rules differ in youth leagues.

Fielding stats

PO: putouts

Outs a fielder records directly, such as catching a fly ball or taking a throw at first.

A: assists

Throws or deflections that help produce an out.

E: errors

A misplay that allows a batter or runner to reach or advance when an ordinary effort would have recorded an out.

FPCT: fielding percentage

(Putouts + Assists) ÷ (Putouts + Assists + Errors).

DP: double plays

Two outs recorded on one play.

PB: passed ball

A catcher's failure to handle a pitch that he should have, allowing runners to advance.

Baserunning stats

SB / CS: stolen bases / caught stealing

Successful and unsuccessful steal attempts. SB% is SB ÷ (SB + CS).

LOB: left on base

Runners still on base when the inning ends.

WP / BK: wild pitch / balk

Pitching events that let runners advance.

Measurables

Showcase and youth baseball also track physical measurements. Treat them as snapshots, and note who recorded them and how.

Exit velocity

How fast the ball leaves the bat, in miles per hour, usually read by radar or a sensor.

Fastball velocity

Pitch speed in mph, measured by radar.

60-yard dash

A standard speed test, timed in seconds.

Pop time

For catchers: the time from the pitch reaching the catcher's mitt to the throw reaching the infielder's glove at second base.

Not sure where these appear in a game? See how to read a baseball box score.