Strikeouts per nine innings, usually written as K/9, tells you how many batters a pitcher fans during a typical nine-inning game.
It removes the effects of innings pitched so you can compare bullpen arms and starters on equal footing.
Enter the total strikeouts and innings the pitcher has thrown to instantly see the rate.
Use it for fantasy roster moves, scouting reports, or just baseball trivia.
Frequently Asked Questions
What is a good K/9 for a starting pitcher?
League average starters usually sit around 8.0.
Anything above 10.0 is considered excellent and signals a true strikeout artist.
Why is K/9 better than total strikeouts?
Total strikeouts depend on how many innings a pitcher has logged.
K/9 removes workload from the equation so two pitchers with different innings totals can be compared fairly.
How do partial innings affect the calculation?
Record the inning exactly as it appears in the box score.
For example, 6 and 1/3 innings becomes 6.1 and 6 and 2/3 innings becomes 6.2.
Use that decimal value in the calculator.
Make sure to input these decimal values accurately to ensure precise results in your bb/9 calculation tool.
Remember that the abbreviation for innings can sometimes lead to confusion, so clarity in your entries is essential.
This attention to detail will help maintain the integrity of your calculations.
What is the difference between K/9 and K%?
K/9 is strikeouts per nine innings, while K% is the percentage of batters faced that the pitcher strikes out.
K% accounts for walks and hits, making it a rate per batter instead of per inning.
Can K/9 be used for relief pitchers?
Yes.
Relievers often work in short bursts and may post very high K/9 numbers.
Comparing K/9 lets you see who brings the most swing-and-miss stuff out of the bullpen.