OBP

From SoSH

On Base Percentage (OBP)

A measure of how often a batter gets to first base (or beyond) for any reason other than a fielding error, fielder's choice, fielder's obstruction or catcher's interference.

The official formula used by MLB is:

OBP = (H + BB + HBP) / (AB + BB + HBP + SF)

Because sacrifice flies count AGAINST OBP but not BA, it is possible to have a lower OBP than BA, though very few Major League players have managed this dubious achievement. Bunts are ignored for the purposes of calculating OBP.

According to FanGraphs, good OBP is greater than .375, average OBP is between .275 and .375 and bad OBP is less than .275. League Average OBP is right around .330