# On Base Percentage (OBP) Calculator (Baseball)

## What is On Base Percentage?

On Base Percentage (OBP) is a baseball statistic used to put a batter’s number of times they get on base in comparison to the number of times they have been at the plate.

It is intended to be a more accurate representation of a batter’s ability to get on base than their batting average – as it includes statistics such as the number of times they have been walked or hit by a pitch, which are not normally  included in statistics that rely only on upon “at bats.”

## How to calculate OBP

In Baseball, on-base percentage calculates as follows:

On Base Percentage (OBP) = (hits + walks + hit by pitch) / (at-bats + walks + hit by pitch + sacrifice flies)

## Example

If a batter has been at bat 127 times and in that time has made: 32 hits, 7 walks, been hit by a pitch 2 times, and 3 sacrifice flies, then:

32 hits + 7 walks + 2 hit by a pitch is 41.

127 at-bats + 7 walks + 2 hit by a pitch + 3 sacrifice flies is 139.

41 divided by 139 is 0.295

Therefore, the batter’s on-base percentage is 0.295.

## What qualifies as a hit?

A hit records when the batter safely reaches first base after hitting the ball into fair territory without the benefit of an error or a fielder’s choice.

If the batter (or runner) attempts another base and is caught out, they are still credited with the hit as long as they have reached 1st base.

## What qualifies as a walk?

A walk occurs when the pitcher has thrown 4 balls before throwing 3 strikes or having the ball hit into play.

## What qualifies as a “hit by pitch”?

A batter is hit by a pitch when the ball hits the batter during the pitching sequence.

## What qualifies as a sacrifice fly?

A sacrifice fly happens when there are less than 2 outs, and the ball is hit into outfield fair or foul territory or to infield foul territory.

If the batter is put out because a fielder catches the ball on the fly, and a runner who is already on base scores on the play, it counts as a sacrifice fly.

It should be noted that sacrifice bunts do not count against a batter’s calculation for on-base percentage like sacrifice flies are.

## What qualifies as an “At Bat”?

An “at bat” is counted each time the player is at bat. At bats are not counted in specific circumstances, including:

• The batter hit by a pitch
• A sacrifice fly or sacrifice hit
• Base on balls
• The inning ends while still at bat
• The batter is replaced by another hitter before the turn completes