From BR Bullpen
For teams, it is calculated thus: (Games Won) / (Games Played)
|All Time Leaders -- Pitchers|
|Career (minimum 100 wins)||Spud Chandler||.717||109 wins|
|Career (minimum 200 wins)||Whitey Ford||.690||236 wins|
|Season (qualifier)||Johnny Allen||.938||1937|
|Season (no losses)||Tom Zachary||1.000||1929, 12-0|
For teams, the highest winning percentage recorded since 1900 is .763, by the 1906 Chicago Cubs, who went 116-36. Since 1903, only 9 teams have played for a winning percentage of .700 or better, the last being the 2001 Seattle Mariners at .716.
 Further Reading
- Douglas Jordan: "The .700 Club: Blessedly Good Baseball", The Baseball Research Journal, SABR, Volume 45, Number 2 (Fall 2016), pp. 26-33.
- John A. Richards: "Probabilities of Victory in Head-to-Head Team Matchups", The Baseball Research Journal, Vol. 43, number 2, Fall 2014, pp. 107-117.