Strikeouts Per 9 Innings K/9

K/9 stands for strikeouts per 9 innings in baseball. How many batters a pitcher strikes out over a full nine innings.

How K/9 is calculated

K/9 = 9 × K ÷ IP

Relievers throw harder in short bursts and post figures starters cannot match, which is why a leaderboard that asks for a qualifying innings total lists starters only. League-wide it has run near 8.5 in recent seasons.

What counts as a good K/9?

Half of the 141 qualified MLB players in 2026 were at or below 8.2. Clearing 10.6 put a season in the top tenth of the league.

Median
8.2
Top 10%
10.6
Leader
13.0

Qualified: 100+ IP, non-zero, 2026 regular season.

Strikeouts Per 9 Innings questions