A player’s batting average is determined by dividing the number of base hits a player has by the total number of at-bats. For example, if a player has 500 at-bats and collects 150 hits in those at-bats, his batting average would be .300 (150/500 = .300). Keep in mind that walks and sacrifice plays (i.e. sacrifice bunts and sacrifice flies) do not count as at-bats, and therefore, do not factor into a player’s batting average.
A batting average of .300 or above is considered an excellent batting average, and an average of .400 for a season is deemed nearly impossible. The last player to hit .400 for a season was Ted Williams, who finished the 1941 seasons with a .406 batting average.