## Calculator

## 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

## Resources

- Wikipedia – On Base Percentage
- Wikipedia – Hit (Baseball)
- Wikipedia – At bat
- Wikipedia – Base on Balls
- Wikipedia – Hit by Pitch
- Wikipedia – Sacrifice Fly
- Wikipedia – Sacrifice Bunt
- Major League Baseball – Official Rules: 10.01 – The Rules of Scoring
- ESPN – MLB Statistics – Batting
- Baseball-reference.com – Career Leaders for OBP
- NCAA – Official Baseball Statistics Rules
- NCAA – Official Softball Statistics Rules
- NCAA – The Official NCAA Baseball and Softball Scorebook
- NFHS – Statistician’s Manual
- International Baseball Federation – Scoring Manual

## Baseball Statistics Calculators

- At Bats per Home Run (ABHR)
- Batting Average (BA)
- Batting Average on Balls in Play (BABIP)
- Walks per 9 Innings (BB/9)
- Walk to Strikeout Ratio (BB/K)
- Batting Park Factor (BFP)
- Component ERA (CERA)
- Defense Independent Component ERA (DICE)
- Earned Run Average (ERA)
- Equivalent Average (EqA)
- Fielding Percentage (FCPT)
- Fielding Percentage (FIP)
- Ground Ball / Fly Ball (GB/FB)
- Ground Outs / Fly Outs (GO/AO)
- Gross Production Average (GPA)
- Hits per 9 Innings (H/9)
- Innings Pitched per Game (IP/GS)
- Isolated Power (ISO)
- Strike to Walk Ratio (K/BB)
- Left on Base Percentage (LOB%)
- On Base Percentage (OBP)
- On Base Plus Slugging (OBPS)
- Opponents Batting Average (OBA)
- Plate Appearances per Strikeout (PA/SO)
- Power Finesse Ratio (PFR)
- Pythagorean Expectation
- Run Average (RA)
- Runs Created (RC)
- Range Factor (RF)
- Runs Produced (RP)
- Stolen Base Percentage (SB%)
- Slugging Percentage (SLG)
- Save Percentage (SV%)
- Total Average (TA)
- Total Bases (TB)
- Total Chances (TC)
- Times on Base (TOB)
- Walks and Hits per Inning Pitched (WHIP)
- Extrapolated runs (XR / XRR / XRB)