.400

In baseball, batting average (AVG) is a measure of a batter's success rate in achieving a hit during an at bat, and is calculated by dividing a player's hits by his at bats. The achievement of a .400 batting average in a season is recognized as "the standard of hitting excellence", in light of how batting .300 in a season is already regarded as solid. Twenty players have recorded a batting average of at least .400 in a single Major League Baseball (MLB) season as of 2016, the last being Ted Williams of the Boston Red Sox in 1941. Three players – Ed Delahanty, Ty Cobb and Rogers Hornsby – have accomplished the feat in three different seasons, and no player has ever hit over .440, a single-season record established by Hugh Duffy in 1894.Ross Barnes was the first player to bat .400 in a season, posting a .429 batting average in the National League's inaugural 1876 season.

In total, 20 players have reached the .400 mark in MLB history and five have done so more than once. Of these, ten were right-handed batters, nine were left-handed, and one was a switch hitter, meaning he could bat from either side of the plate. Two of these players (Terry and Williams) played for only one major league team. The Philadelphia Phillies are the only franchise to have four different players reach the milestone while on their roster: Delahanty, Billy Hamilton, Sam Thompson, and Tuck Turner, all of whom attained a batting average over .400 during the 1894 season. Three players won the Most Valuable Player (MVP) Award in the same year as their .400 season.Tip O'Neill, Nap Lajoie, and Hornsby are the only players to have earned the Triple Crown alongside achieving a .400 batting average, leading their respective leagues in batting average, home runs and runs batted in (RBI). Although Shoeless Joe Jackson's .408 batting average in 1911 did not earn him the American League's batting title, it established a major league record for a rookie that stands to this day.Fred Dunlap has the lowest career batting average among players who have batted .400 in a season with .292, while Cobb – with .366 – recorded the highest career average in major league history.

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