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How to Calculate On-Base Percentage (OBP)

A crucial statistic for determining a player's worth, on-base percentage was created in the 1950s. You can figure the OBP for your favorite baseball players by following a simple formula.


  • Step 1: Divide the total from your first calculation -- hits plus bases on balls plus hit by pitch -- by the total from your second calculation -- at bats plus walks plus hit by pitch plus sacrifice flies -- to get the players on base percentage, or OBP.
  • FACT: As of the 2010 season, Barry Bonds held the MLB record for on base percentage at .609.
  • Step 2: Add the players total number of at bats, walks -- including hit-by-pitch -- and sacrifice flies.
  • TIP: Do not include the at bats when the player reached because of an error or a fielder's choice.
  • Step 3: Write down and add the number of times the player reached base as the result of a hit, base on balls, and being hit by a pitch.
  • Step 4: Account for every plate appearance of the batter whose on-base percentage you're going to calculate. Subtract sacrifices from the total plate appearances to get the player's total number of official at bats.

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