In baseball, run differential is the subtraction of runs scored for a team and runs allowed by a team. The run differential is positive if a team scores more runs than allowed, while it is negative if a team allows more runs than scored for. Run differential can be used to predict the expected win total for a team. The differences in records between close games and blowout games can deviate the actual win–loss record from expected record based on run differential.
The best run differential in a MLB season is +411, set by the New York Yankees in 1939 in which they scored 967 runs and allowed 556 runs. The worst run differential is the Cleveland Spiders in 1899 at −723 (529 runs scored, 1252 runs allowed). The highest run differential in a single game in major league history is 29, when the Chicago Colts (now the Cubs) beat the Louisville Colonels 36–7 on June 29, 1897, and the record in modern history is 27, when the Texas Rangers beat the Baltimore Orioles 30–3 on August 22, 2007. The biggest run differential in a shutout is 22, when the Cleveland Indians defeated the New York Yankees 22–0 on August 31, 2004.