Inbaseball statistics,walks plus hits per inning pitched (WHIP) is asabermetric measurement of the number ofbaserunners apitcher has allowed perinning pitched. WHIP is calculated by adding the number ofwalks andhits allowed and dividing this sum by the number of innings pitched.[1]
WHIP reflects a pitcher's propensity for allowingbatters to reach base, therefore a lower WHIP indicates better performance.
Whileearned run average (ERA) measures the earnedruns a pitcher gives up, WHIP more directly measures a pitcher's effectiveness against batters.[1] Like ERA, WHIP accounts for pitcher performance disregardingerrors andunearned runs.[note 1]
The stat was invented in 1979 by writerDaniel Okrent,[1] who called the metric "innings pitched ratio" at the time. Okrent excludedhit batsmen from the numerator of baserunners allowed since Sunday newspapers did not include hit batsmen in theiragatebox scores.[2]
WHIP is one of the few sabermetric statistics to enter mainstream baseball usage.[2] In addition to its use in live games, the WHIP is one of the most commonly used statistics infantasy baseball, and is standard in fantasy leagues that employ4×4, 5×5, and 6×6 formats.
WHIP near 1.000 or lower over the course of aseason will often rank among the league leaders inMajor League Baseball (MLB).
The lowest single-season WHIP in MLB history through 2025 is held byPedro Martínez of the 2000Boston Red Sox, with a WHIP of 0.7373 which broke the previous record of 0.7803 ofWalter Johnson of the 1913Washington Senators.[3] The second-lowest single-season WHIP is held byKenta Maeda of the 2020Minnesota Twins, with a WHIP of 0.7500; the third-lowest single-season WHIP is held byGuy Hecker, with .7692 in 1882; the fourth-lowest single-season WHIP is held by the previously mentionedWalter Johnson of the 1913Washington Senators, with a WHIP of 0.7803.[3]
Cleveland Broncos/Naps (currently the Guardians) right-handed pitcherAddie Joss holds the MLB record for the lowest career WHIP as of 2024, with a 0.9678 WHIP in 2,327 innings.[1] Active pitcherJacob deGrom of theTexas Rangers currently holds a career 0.9941 WHIP in 1367 innings and holds second.Chicago White SoxspitballerEd Walsh is third, with a 0.9996 WHIP in 2,9641⁄3 innings, the lowest career WHIP for a qualified pitcher with 10 or more seasons pitched.[4] RelieverMariano Rivera ranks fourth among qualified pitchers with a career WHIP of 1.0003 in 1,2832⁄3 innings.[4]Los Angeles Dodgers left-handed pitcherClayton Kershaw ranks fifth with a WHIP of 1.0096 in 2,7422⁄3 innings.[4]