Single Season Leaders for Isolated Power in the National League

Isolated Power is a SABERmetric statistic that attempts to describe a hitter's overall effectiveness by measuring his ability to generate extra base hits. Isolated Power was created by baseball great Branch Rickey along with Allan Roth during the 1950's and they termed it Power Average. Isolated Power is calculated by substracting batting average from slugging percentage.

Important notes: One-hundred single season games played are needed to make this list, raw averages are presented to further clarify the one-hundred greatest single season National League isolated power averages of all-time, and a bold faced entry denotes that the player was active during the previous season.
"Barry Bonds will go down in baseball history as the greatest player that ever played the game. He will over time become a larger legend than Babe Ruth, Ty Cobb or Hank Aaron. He will most likely hold the single season and all time home run records before his career ends. His 73 home runs in one season may never be broken." - Barry Bonds Power Surge (beauproductions.com)
Isolated Power
Single Season National League Leaders

'Top 100'
Barry Bonds .536 (.53571) 2001 San Francisco Giants NL 1
Mark McGwire .454 (.45383) 1998 St. Louis Cardinals NL 2
Barry Bonds .450 (.45040) 2004 San Francisco Giants NL 3
Barry Bonds .429 (.42928) 2002 San Francisco Giants NL 4
Mark McGwire .418 (.41843) 1999 St. Louis Cardinals NL 5
Sammy Sosa .409 (.40901) 2001 Chicago Cubs NL 6
Barry Bonds .408 (.40769) 2003 San Francisco Giants NL 7
Jeff Bagwell .383 (.38250) 1994 Houston Astros NL 8
Barry Bonds .381 (.38125) 2000 San Francisco Giants NL 9
Hack Wilson .368 (.36752) 1930 Chicago Cubs NL 10
Luis Gonzalez .363 (.36289) 2001 Arizona Diamondbacks NL 11
Javy Lopez .359 (.35886) 2003 Atlanta Braves NL 12
Barry Bonds .355 (.35493) 1999 San Francisco Giants NL 13
Larry Walker .354 (.35387) 1997 Colorado Rockies NL 14
Rogers Hornsby .353 (.35317) 1925 St. Louis Cardinals NL 15
Todd Helton .349 (.34923) 2001 Colorado Rockies NL 16
Ralph Kiner .348 (.34791) 1949 Pittsburgh Pirates NL 17
Sammy Sosa .347 (.34720) 1999 Chicago Cubs NL 18
Willie Stargell .347 (.34674) 1973 Pittsburgh Pirates NL 19
Ryan Howard .346 (.34596) 2006 Philadelphia Phillies NL 20
Kevin Mitchell .344 (.34438) 1989 San Francisco Giants NL 21
Jim Edmonds .342 (.34228) 2003 St. Louis Cardinals NL 22
Hank Aaron .342 (.34184) 1973 Atlanta Braves NL 23
Hank Aaron .341 (.34141) 1971 Atlanta Braves NL 24
Barry Bonds .341 (.34137) 1993 San Francisco Giants NL 25
Jim Edmonds .341 (.34137) 2004 St. Louis Cardinals NL  
Albert Pujols .340 (.34019) 2006 St. Louis Cardinals NL 27
Willie Mays .340 (.33966) 1955 New York Giants NL 28
Matt Williams .339 (.33933) 1994 San Francisco Giants NL 29
Sammy Sosa .339 (.33904) 1998 Chicago Cubs NL 30
Mike Schmidt .338 (.33759) 1980 Philadelphia Phillies NL 31
Willie McCovey .336 (.33605) 1969 San Francisco Giants NL 32
Barry Bonds .335 (.33504) 1994 San Francisco Giants NL 33
Willie Stargell .333 (.33268) 1971 Pittsburgh Pirates NL 34
Tony Clark .332 (.33238) 2005 Arizona Diamondbacks NL 35
Larry Walker .331 (.33105) 1999 Colorado Rockies NL 36
Prince Fielder .330 (.32984) 2007 Milwaukee Brewers NL 37
Willie Mays .328 (.32796) 1965 San Francisco Giants NL 38
Mike Schmidt .328 (.32768) 1981 Philadelphia Phillies NL 39
Derrek Lee .327 (.32660) 2005 Chicago Cubs NL 40
Albert Pujols .326 (.32601) 2004 St. Louis Cardinals NL 41
Todd Helton .326 (.32586) 2000 Colorado Rockies NL 42
Stan Musial .326 (.32570) 1948 St. Louis Cardinals NL 43
Ralph Kiner .326 (.32566) 1947 Pittsburgh Pirates NL 44
Dave Kingman .325 (.32519) 1979 Chicago Cubs NL 45
Eddie Mathews .325 (.32470) 1953 Milwaukee Braves NL 46
Greg Vaughn .325 (.32461) 1998 San Diego Padres NL 47
Brian Giles .324 (.32394) 2002 Pittsburgh Pirates NL 48
Willie McCovey .323 (.32323) 1970 San Francisco Giants NL 49
Richard Hidalgo .323 (.32258) 2000 Houston Astros NL 50
Willie Mays .322 (.32212) 1954 New York Giants NL 51
Johnny Mize .321 (.32124) 1940 St. Louis Cardinals NL 52
Rogers Hornsby .321 (.32103) 1922 St. Louis Cardinals NL 53
Duke Snider .320 (.31970) 1955 Brooklyn Dodgers NL 54
Carlos Beltran .320 (.31961) 2006 New York Mets NL 55
Vladimir Guerrero .319 (.31874) 2000 Montreal Expos NL 56
Ralph Kiner .318 (.31827) 1951 Pittsburgh Pirates NL 57
Ralph Kiner .318 (.31810) 1950 Pittsburgh Pirates NL 58
Gary Sheffield .317 (.31737) 2000 Los Angeles Dodgers NL 59
Chick Hafey .316 (.31614) 1930 St. Louis Cardinals NL 60
Ted Kluszewski .316 (.31588) 1954 Cincinnati Redlegs NL 61
Ryan Howard .316 (.31569) 2007 Philadelphia Phillies NL 62
Dick Allen .315 (.31489) 1966 Philadelphia Phillies NL 63
Sammy Sosa .315 (.31457) 2000 Chicago Cubs NL 64
Chipper Jones .314 (.31393) 1999 Atlanta Braves NL 65
Eddie Mathews .313 (.31303) 1954 Milwaukee Braves NL 66
Duke Snider .313 (.31299) 1957 Brooklyn Dodgers NL 67
Barry Bonds .313 (.31290) 1992 Pittsburgh Pirates NL 68
Eddie Mathews .313 (.31263) 1955 Milwaukee Braves NL 69
Andruw Jones .312 (.31229) 2005 Atlanta Braves NL 70
Johnny Mize .312 (.31229) 1947 New York Giants NL  
Larry Walker .312 (.31187) 2001 Colorado Rockies NL 72
Willie Mays .311 (.31142) 1964 San Francisco Giants NL 73
Willie Mays .311 (.31079) 1962 San Francisco Giants NL 74
George Foster .311 (.31057) 1977 Cincinnati Reds NL 75
Mike Schmidt .311 (.31054) 1979 Philadelphia Phillies NL 76
Ryan Braun .310 (.31042) 2007 Milwaukee Brewers NL 77
Jack Clark .310 (.31026) 1987 St. Louis Cardinals NL 78
Gary Sheffield .310 (.31021) 1996 Florida Marlins NL 79
Bob Bailey .310 (.30966) 1970 Montreal Expos NL 80
Albert Pujols .308 (.30795) 2003 St. Louis Cardinals NL 81
Barry Bonds .308 (.30754) 1996 San Francisco Giants NL 82
Hank Aaron .307 (.30713) 1969 Atlanta Braves NL 83
Jim Thome .307 (.30709) 2004 Philadelphia Phillies NL 84
Duke Snider .307 (.30651) 1954 Brooklyn Dodgers NL 85
Mel Ott .306 (.30642) 1929 New York Giants NL 86
Duke Snider .306 (.30627) 1956 Brooklyn Dodgers NL 87
Jim Thome .306 (.30623) 2003 Philadelphia Phillies NL 88
Joe Adcock .306 (.30617) 1956 Milwaukee Braves NL 89
Barry Bonds .306 (.30616) 1998 San Francisco Giants NL 90
Lance Berkman .306 (.30597) 2006 Houston Astros NL 91
Sammy Sosa .306 (.30576) 2002 Chicago Cubs NL 92
Jeff Bagwell .306 (.30565) 1997 Houston Astros NL 93
Jeff Bagwell .305 (.30508) 2000 Houston Astros NL 94
Wally Berger .305 (.30450) 1930 Boston Braves NL 95
Fred McGriff .304 (.30425) 1994 Atlanta Braves NL 96
Jim Bottomley .304 (.30382) 1928 St. Louis Cardinals NL 97
Adam Dunn .303 (.30282) 2004 Cincinnati Reds NL 98
Chuck Klein .302 (.30195) 1929 Philadelphia Phillies NL 99
Larry Walker .302 (.30162) 1995 Colorado Rockies NL 100
Current Through End of 2007 Regular Season


Did you know this stat was originally called Power Average? Did you know it had been around for the past fifty (50) years? Should Isolated Power be more commonly used & quoted by the media? Join in our advanced baseball stats forum on Baseball Fever?

The code to write the single season isolated power league splits was developed in 2005, launched during 2006 and made possible by your support — please continue helping us create these kinds of pages by supporting our site.

The American League single season record for isolated power was set in 1920 by Babe Ruth of the New York Yankees. The National League single season record for isolated power is on this page. Is either the Career Leader for Isolated Power?
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