Ted Williams is the all-time Major League Baseball leader in on-base percentage.

In baseball statistics, on-base percentage (OBP) measures how frequently a batter reaches base. An official Major League Baseball (MLB) statistic since 1984, it is sometimes referred to as on-base average (OBA),[a] as it is rarely presented as a true percentage.

Generally defined as "how frequently a batter reaches base per plate appearance",[1] OBP is specifically calculated as the ratio of a batter's times on base (the sum of hits, bases on balls, and times hit by pitch) to the sum of at bats, bases on balls, hit by pitch, and sacrifice flies.[1] OBP does not credit the batter for reaching base on fielding errors, fielder's choice, uncaught third strikes, fielder's obstruction, or catcher's interference.

OBP is added to slugging average (SLG) to determine on-base plus slugging (OPS).

The OBP of all batters faced by one pitcher or team is referred to as "on-base against".

On-base percentage is calculable for professional teams dating back to the first year of National Association of Professional Base Ball Players competition in 1871,[2] because the component values of its formula have been recorded in box scores ever since.


The statistic was invented in the late 1940s by Brooklyn Dodgers statistician Allan Roth with then-Dodgers general manager Branch Rickey.[3][4] In 1954, Rickey, who was then the general manager of the Pittsburgh Pirates, was featured in a Life Magazine graphic in which the formula for on-base percentage was shown as the first component of an all-encompassing "offense" equation.[5] However, it was not named as on-base percentage, and there is little evidence that Roth's statistic was taken seriously at the time by the baseball community at large.[6]

On-base percentage became an official MLB statistic in 1984. Its perceived importance jumped after the influential 2003 book Moneyball highlighted Oakland Athletics general manager Billy Beane's focus on the statistic.[7] Many baseball observers, particularly those influenced by the field of sabermetrics, now consider on-base percentage superior to the statistic traditionally used to measure offensive skill, batting average,[8][9] which accounts for hits but ignores other ways a batter can reach base.[10]


Traditionally, players with the best on-base percentages bat as leadoff hitter, unless they are power hitters, who traditionally bat slightly lower in the batting order. The league average for on-base percentage in Major League Baseball has varied considerably over time; at its peak in the late 1990s, it was around .340, whereas it was typically .300 during the dead-ball era. On-base percentage can also vary quite considerably from player to player. The highest career OBP of a batter with more than 3,000 plate appearances is .482 by Ted Williams. The lowest is by Bill Bergen, who had an OBP of .194.

On-base percentage is calculated using this formula:[11][12][13]


In certain unofficial calculations, the denominator is simplified and replaced by Plate Appearance (PA); however, the calculation PAs includes certain infrequent events that will slightly lower the calculated OBP (i.e. catcher's interference, and sacrifice bunts).[13] Sacrifice bunts are excluded from consideration on the basis that they are usually imposed by the manager with the expectation that the batter will not reach base, and thus do not accurately reflect the batter's ability to reach base when attempting to do so. This is in contrast with the sacrifice fly, which is generally unintentional; the batter was trying for a hit.[1]

All-time leaders

# Player OBP[14] Team(s) Year(s)
1 Ted Williams .4817 Boston Red Sox 19391942, 19461960
2 Babe Ruth .4740 Boston Red Sox, New York Yankees, Boston Braves 19141935
3 John McGraw .4657 Baltimore Orioles, St. Louis Cardinals, New York Giants 18911906
4 Billy Hamilton .4552 Kansas City Cowboys, Philadelphia Phillies, Boston Beaneaters 18881901
5 Lou Gehrig .4474 New York Yankees 19231939
6 Barry Bonds .4443 Pittsburgh Pirates, San Francisco Giants 19862007
7 Bill Joyce .4349 Brooklyn Ward's Wonders, Boston Reds, Brooklyn Grooms, Washington Senators, New York Giants 18901898
8 Rogers Hornsby .4337 St. Louis Cardinals, New York Giants, Boston Braves, Chicago Cubs, St. Louis Browns 19151937
9 Ty Cobb .4330 Detroit Tigers, Philadelphia Athletics 19051928
10 Jimmie Foxx .4283 Philadelphia Athletics, Boston Red Sox, Chicago Cubs, Philadelphia Phillies 19251942, 19441945
11 Tris Speaker .4279 Boston Red Sox, Cleveland Indians, Washington Senators, Philadelphia Athletics 19071928
12 Eddie Collins .4244 Philadelphia Athletics, Chicago White Sox 19061930

Single-season leaders

# Player OBP[15] Team Year
1 Barry Bonds .6094 San Francisco Giants 2004
2 Barry Bonds .5817 San Francisco Giants 2002
3 Ted Williams .5528 Boston Red Sox 1941
4 John McGraw .5475 Baltimore Orioles 1899
5 Babe Ruth .5445 New York Yankees 1923
6 Babe Ruth .5319 New York Yankees 1920
7 Barry Bonds .5291 San Francisco Giants 2003
8 Ted Williams .5256 Boston Red Sox 1957
9 Billy Hamilton .5209 Philadelphia Phillies 1894
10 Babe Ruth .5156 New York Yankees 1926

See also


  1. ^ Not to be confused with opponents' batting average (OBA), more commonly known as batting average against (BAA).


  1. ^ a b c "Glossary / Standard Stats / On-base Percentage (OBP)". MLB.com. Retrieved 13 June 2018.
  2. ^ "Yearly League Leaders & Records for On-Base%". Baseball-Reference.com. Retrieved 2020-07-01.
  3. ^ "What is a On-base Percentage (OBP)? | Glossary". Major League Baseball. Retrieved 2020-07-01.
  4. ^ "Allan Roth – Society for American Baseball Research". Retrieved 2020-07-01.
  5. ^ Rickey, Branch (August 2, 1954). "Goodby to Some Old Baseball Ideas". Life. Retrieved July 1, 2020.
  6. ^ Schwarz, Alan (2004). The Numbers Game: Baseball's Lifelong Fascination with Statistics. New York: St. Martin's Press. p. 55. ISBN 9780312322229.
  7. ^ "Prospectus Idol Entry: Why is On Base Percentage King?". Baseball Prospectus. 2009-05-23. Retrieved 2020-07-01.
  8. ^ "My plea to mainstream on-base percentage instead of batting average". CBSSports.com. 16 November 2012. Retrieved 2020-07-01.
  9. ^ "Stat to the Future: Why it's time to stop relying on batting average". www.sportingnews.com. 17 August 2017. Retrieved 2020-07-01.
  10. ^ "OBP | Sabermetrics Library". Retrieved 2020-07-01.
  11. ^ "Baseball reference: OBP".
  12. ^ Cole, Bryan (2014-07-17). "Should the OBP formula include errors?". Beyond the Box Score. Retrieved 2022-01-14.
  13. ^ a b "Fangraphs".
  14. ^ "Career Leaders for On Base Percentage". Sports Reference, Inc. Retrieved 2011-06-25.
  15. ^ "Single Season League Leaders for On-Base Percentage". Sports Reference, Inc. Retrieved 2011-06-25.