On Base Percentage measures the rate at which a batter gets on base for any reason excluding fielding errors, fielder's choice, fielder's obstruction, or catcher's interference.
On Base Percentage = Hits (H) + Base on Balls (BB) + Hit By Pitch (HBP) / At Bats (AB) + BB + HBP + Sacrifice Flies (SF)
More about On Base Percentage Leaders
Player On Base Percentage Leaders are those who are most likely safely reach base via a hit, walk, hit by pitch, or catcher’s interference. In recent years on OBP of .400 (meaning the batter safely reached base approximately 40% of the time) will put a player among the league leaders, though a decade ago an OBP of closer to .450 was needed to top the leaderboards. These hitters are generally among the best in the game – to have a high on-base percentage usually (but not always) requires a player to have both a higher than average batting average and to accumulate a higher than average number of walks (hit by pitch and catcher’s interference make up a small number of ways a batter safely reaches base).