WHIP and Pitching Rates Calculator
WHIP and Pitching Rates Calculator
Walks plus hits per inning pitched, with strikeouts per nine, walks per nine and strikeouts per walk — worked from the innings and outs, because a baseball pitching line of 200.1 is 200 innings and one out. WHIP counts no hit batsman, which surprises people.
WHIP, K/9, BB/9 and K/BB
Walks and hits per inning180 hits and 55 walks allowed with 210 strikeouts in 200 complete innings and 1 further out
Four rates, one denominator, and what WHIP ignores
K/9 = strikeouts × 9 ÷ innings pitched
BB/9 = walks × 9 ÷ innings pitched
K/BB = strikeouts ÷ walks
- WHIP
- MLB’s glossary: “it’s the sum of a pitcher’s walks and hits, divided by his total innings pitched”. It is baserunners allowed per inning, so about one is good and about one and a half is poor
- what WHIP does NOT count
- “Hit batsmen, errors and hitters who reach via fielder’s choice do not count against a pitcher’s WHIP”, in MLB’s own words. A pitcher who hits ten batters has put ten men on base that the statistic cannot see, while the earned runs they produce are fully in the ERA
- the nine in K/9 and BB/9
- the same nine as in the ERA: these are per-complete-game rates. MLB gives K/9 as “dividing his strikeout total by his innings pitched total and multiplying the result by nine”. A seven-inning competition’s figures are not comparable with a nine-inning competition’s
- K/BB, and where it stops existing
- strikeouts divided by walks, which MLB calls “an essential tool for evaluating pitchers”. With no walks it is undefined, not infinite, and this page withholds the row rather than printing something
- baseball has no “strike rate”
- the phrase belongs to cricket, where it means two different things depending on whose it is: a batter’s runs per 100 balls, or a bowler’s balls per wicket. Baseball’s nearest figures are the two above, and neither is in the same units as either cricket quantity
Worked example
180 hits and 55 walks allowed with 210 strikeouts in 200 complete innings and 1 further out
Innings pitched = 200 + 1 ÷ 3 = 200.333 innings, which is 601 outs
WHIP = (180 + 55) ÷ 200.333 = 235 ÷ 200.333 = 1.17 baserunners per inning
K/9 = 210 × 9 ÷ 200.333 = 9.43 strikeouts per nine innings
BB/9 = 55 × 9 ÷ 200.333 = 2.47 walks per nine innings
K/BB = 210 ÷ 55 = 3.82 strikeouts for every walk
Double the numerator and the denominator and the WHIP does not move: 360 hits and 110 walks in 400 innings and 2 outs is 470 ÷ 400.667 = 1.17 again
Take the innings down to 100 and 0 outs and the WHIP rises to 235 ÷ 100 = 2.35, slightly more than double, because 100 innings is slightly less than half of 200 1/3
Set the walks to 0 and the strikeouts-per-walk row disappears rather than printing a zero or an infinity
What each pitching rate counts, and what it cannot see
| Figure | Numerator | Denominator | Blind to |
|---|---|---|---|
| WHIP | walks + hits | innings pitched | hit batsmen, errors, fielder’s choice — MLB says so |
| ERA | earned runs × 9 | innings pitched | unearned runs, by design, and so partly blind to the defence |
| K/9 | strikeouts × 9 | innings pitched | how many batters it took to get there |
| BB/9 | walks × 9 | innings pitched | hit batsmen, which also put a runner on |
| K/BB | strikeouts | walks | everything else, and it stops existing at zero walks |
“Strike rate” in two sports, which is three quantities
| Phrase | Sport | What it is | Better is |
|---|---|---|---|
| Batting strike rate | Cricket | runs per 100 balls faced | higher |
| Bowling strike rate | Cricket | balls bowled per wicket | lower |
| Strikeouts per nine innings | Baseball | strikeouts per nine innings pitched | higher |
| Strikeouts per walk | Baseball | strikeouts per walk issued | higher |
WHIP is baserunners per inning, and the denominator is in thirds
WHIP answers one question: how many batters did this pitcher put on base for every inning worked? MLB’s glossary gives the arithmetic plainly — “it’s the sum of a pitcher’s walks and hits, divided by his total innings pitched” — and the attraction of it is that, unlike an earned run, every term is a count rather than a judgement.
No governing body defines this. The Official Baseball Rules define only the percentages listed in Rule 9.21, and this is not among them: Major League Baseball publishes it in its own statistics glossary rather than in its rulebook. That is not a reason to distrust the arithmetic — it is universal in published records — but it is the reason this page cites a glossary entry and no rule number.
What WHIP leaves out is worth knowing before you compare two pitchers with it. MLB states the exclusions in its own words: “Hit batsmen, errors and hitters who reach via fielder’s choice do not count against a pitcher’s WHIP.” A pitcher who hits ten batters over a season has put ten runners on base that the figure cannot see — and those runners score, and those runs are earned, so they land in full on the earned run average instead. Two pitchers with the same WHIP can have put a materially different number of men on base.
An inning is three outs, and baseball writes a part-finished inning as a figure that looks like a decimal and is not one: 5.2 means five innings and two outs, which is 5 + 2/3 = 5.667 innings. Dividing by 5.2 instead makes the rate about 9% too high at that length. This page therefore takes the innings and the outs as two separate fields, and the outs field cannot go above 2, because a third out finishes the inning and the figure rolls over. On a full season the error is small — two outs misread cost about a fifth of a percent over 200 innings — but on a reliever’s line it is not: two innings and two outs divided as 2.2 rather than 2.667 overstates every rate on this page by 21%. The ERA page probes that error at eight workloads and prints the spread, because the relative size of it depends entirely on how many innings the fixed shortfall is divided into.
One terminological warning, because this site also covers cricket. Baseball has no statistic called a “strike rate”. Cricket has two, and they are not versions of each other: a batter’s strike rate is runs per 100 balls faced and higher is better, while a bowler’s strike rate is balls bowled per wicket and lower is better. Baseball’s nearest equivalents are the two strikeout figures above, in units of innings and walks. None of the four converts into any of the others, and the bowling economy, average and strike rate calculator works the cricket pair, including the economy rate that is the closest thing cricket has to an ERA.
The hitters’ side of these pages is the batting average, OBP and SLG calculator and the wOBA calculator. For why a pitcher’s run prevention and a team’s win total are not the same question, the Pythagorean expectation calculator takes runs scored and runs allowed and asks what win total they imply.
Frequently asked questions
How do you calculate WHIP?
Add the walks to the hits and divide by the innings pitched. 235 baserunners in 200 1/3 innings is 235 ÷ 200.333 = 1.17. Use the true innings, not the published line read as a decimal: 200.1 means 200 innings and one out.
Does WHIP include hit batsmen?
No. MLB’s glossary says in so many words that “Hit batsmen, errors and hitters who reach via fielder’s choice do not count against a pitcher’s WHIP”. A pitcher who hits batters rather than walking them keeps a WHIP that does not reflect the runners allowed, although the runs they score do reach the ERA.
What is a good WHIP?
No governing body publishes a threshold, so none is invented here. As a rough reading of the statistic rather than a standard, a WHIP near 1.00 means about one baserunner an inning and is very good, and one near 1.50 means about half again as many. Compare within one competition and one era, because the run environment moves.
What does K/9 mean, and is it a strike rate?
Strikeouts per nine innings pitched — MLB computes it by “dividing his strikeout total by his innings pitched total and multiplying the result by nine”. It is not a strike rate: that phrase is cricket’s, where it means runs per 100 balls for a batter and balls per wicket for a bowler. Baseball does not use it.
Why does the strikeouts-per-walk figure disappear?
Because the walks are zero, and strikeouts per no walks is undefined rather than infinite. The page withholds the row instead of printing a number, which is the honest answer for a pitcher who has not walked anybody yet.
Related calculators
References
- Major League Baseball. Glossary: Walks And Hits Per Inning Pitched (WHIP) — “it’s the sum of a pitcher’s walks and hits, divided by his total innings pitched”, and “Hit batsmen, errors and hitters who reach via fielder’s choice do not count against a pitcher’s WHIP.” mlb.com (read 12 Oct 2026).
- Major League Baseball. Glossary: Strikeouts Per Nine Innings (K/9) — “dividing his strikeout total by his innings pitched total and multiplying the result by nine”, with the caveat that “there are many successful pitchers who get by with lower K/9 rates”; and Strikeout-to-walk Ratio (K/BB) — “dividing a pitcher’s total number of strikeouts by his total number of walks”. mlb.com (read 12 Oct 2026).
- Major League Baseball. Glossary: Innings Pitched (IP) — “Because there are three outs in an inning, each out recorded represents one-third of an inning pitched.” The entry does NOT state the “.1 and .2” scorebook notation, so this page demonstrates the notation from published lines instead. mlb.com (read 12 Oct 2026).
- Major League Baseball. Glossary: Earned Run Average (ERA) — ERA “represents the number of earned runs a pitcher allows per nine innings”, “with earned runs being any runs that scored without the aid of an error or a passed ball”, and “The formula for finding ERA is: 9 x earned runs / innings pitched.” It does not explain the 9. mlb.com (read 12 Oct 2026).
- Official Baseball Rules, Rule 9.21, Determining Percentage Records — (a) winning percentage; (b) batting average, hits ÷ times at bat; (c) slugging percentage, total bases on safe hits ÷ at-bats; (d) fielding average, putouts plus assists ÷ total chances (putouts, assists, errors); (e) earned-run average, earned runs × 9 ÷ innings pitched, with a Comment working 3 earned runs in 9 1/3 innings as 2.89; (f) on-base percentage, hits plus walks plus hit-by-pitches ÷ at-bats plus walks plus hit-by-pitches plus sacrifice flies. Read on baseballrulesacademy.com, 12 Oct 2026: the official 2024 Edition PDF was fetched whole and its extracted text of 109,942 characters stops inside Rule 5.09, while its own contents page lists Rule 9.21 on page 141. Every formula taken from it is corroborated against MLB’s glossary.