In baseball scorekeeping and stats, “K” means a strikeout. When people talk about “K’s” in baseball, they’re talking about how many batters a pitcher has struck out.

Quick Scoop: What are K’s in baseball?

  • A “K” = one strikeout by a pitcher.
  • “K’s” (plural) = the total number of strikeouts a pitcher has in a game, season, or career, depending on context.
  • On TV graphics or scoreboards, a rising count of K’s shows how dominant a pitcher is that day.

Why the letter K?

The use of K for strikeout goes back to 19th‑century scoring systems created by Henry Chadwick, an early baseball writer. He couldn’t use “S” because it was already taken (for things like sacrifice), so he chose K from “struck,” which was then the common term for a batter being put out on strikes.

Regular K vs. backwards K

  • Normal “K”: the batter struck out swinging at the third strike.
  • Backwards “K” (often drawn as ꓘ on signs or graphics): the batter struck out looking , meaning they did not swing at the third strike.

Fans often hang big letter K signs on the railings in the stands—each K is one strikeout for the home pitcher, and you’ll sometimes see long rows of them in a dominant outing.

Where you’ll see K’s

  • Box scores and stat lines:
    • “K” in pitching stats = strikeouts.
* You might see something like: 7.0 IP, 3 H, 1 ER, 2 BB, 10 K.
  • In-game score bug:
    • A small “K” with a number, like “K: 6,” means the pitcher has 6 strikeouts so far.
  • Fan signs and chants:
    • Fans sometimes chant “K! K! K!” when a pitcher has two strikes and is going for another strikeout.

Simple example

If a pitcher finishes a game with 9 K’s, that just means they struck out 9 different batters (or got 9 total strikeout outs; a player can strike out more than once).

TL;DR: “K’s in baseball” are strikeouts—each K is one batter the pitcher retired on strikes, and lots of K’s usually means the pitcher was dealing.

Information gathered from public forums or data available on the internet and portrayed here.