Baseball Glossary › Strikeout-to-Walk Ratio
Strikeout-to-Walk Ratio (K/BB)
Strikeout-to-walk ratio (K/BB) tells you how many strikeouts a pitcher records for each walk he allows. Divide total strikeouts by total walks. A K/BB of 3.00 means three strikeouts for every walk. It compares a pitcher's best self-made outcome with his worst, so it is a quick read on command and dominance.
Formula
Worked example (illustrative numbers): a pitcher has 210 strikeouts and 60 walks.
K/BB = 210 / 60 = 3.50
He strikes out three and a half batters for every one he walks
Athletics example: Dennis Eckersley
Dennis Eckersley finished with 2,401 strikeouts and 738 walks. See the full career line on the Dennis Eckersley player page.
K/BB = 2,401 / 738 = 3.25
Career MLB totals from our player database (MLB Stats API).
What to Know
K/BB combines the two numbers in strikeouts per nine innings and walks per nine innings. Dividing K/9 by BB/9 gives the same ratio, because the innings cancel out.
Because it is a ratio, K/BB can mislead at the extremes. A pitcher with very few walks can post a huge K/BB without many strikeouts. Some analysts prefer K% minus BB%, which uses strikeout rate and walk rate per batter faced.
MLB's glossary calls K/BB an essential tool for evaluating pitchers. Higher is better, and it pairs well with WHIP when you want to know whether a pitcher's baserunners come from walks or hits.
Frequently Asked Questions
What is K/BB in baseball?
K/BB is the strikeout-to-walk ratio. It is a pitcher's total strikeouts divided by total walks, showing how many batters he strikes out for each one he walks.
How do you calculate strikeout to walk ratio?
Divide strikeouts by walks. A pitcher with 210 strikeouts and 60 walks has a K/BB of 3.50. You can also divide K/9 by BB/9 and get the same answer.
Is a higher strikeout to walk ratio better?
Yes. A higher K/BB means a pitcher misses bats while rarely giving away free bases. A ratio below 1.00 means he walks more hitters than he strikes out.
What is the difference between K/BB and K-BB%?
K/BB divides strikeouts by walks. K-BB% subtracts walk rate from strikeout rate, both measured per batter faced. K-BB% avoids the inflated ratios that pitchers with very few walks can produce.
Does the strikeout to walk ratio apply to hitters?
It can. For hitters, the ratio is usually flipped and read as walks per strikeout, where a higher number signals a disciplined batter who rarely chases pitches outside the zone.
What does K stand for in K/BB?
K is the scorekeeping symbol for a strikeout and BB stands for base on balls, the official term for a walk. K/BB reads as strikeouts per walk.
Related Terms
Sources
- MLB.com Glossary: Strikeout-to-walk Ratio (K/BB)
- FanGraphs Sabermetrics Library: Strikeout and Walk Rates
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