On-base percentage (abbreviated OBP) is a baseball statistic designed to track the rate at which a hitter reaches base as a result of his own actions (as opposed to, for example, defensive lapses). Another way to interpret OBP is the percentage of a player's plate appearances that he does not make an out.
The formula for on-base percentage is
- H is Hits
- BB is Walks
- HBP is times hit by a pitch
- AB is At bats
- SF is Sacrifice Flies
Because there is a high correlation between OBP and runs scored, the use of on-base percentage in player evaluation has gained favor among baseball enthusiasts and front offices in recent years. It has proven to be a more reliable indicator of a player's offensive performance than batting average.