Baseball Reference Glossary

Wins Above Replacement (WAR)

 What is Wins Above Replacement?

Wins Above Replacement, popularly known as WAR, is an advanced baseball statistic that accounts for every action a player takes on the field. That means that WAR presents a single number that represents an estimate of a player’s entire overall value: their hitting (or pitching, for pitchers), fielding, baserunning, and more.

WAR attempts to isolate only the factors in a player’s control in order to present the value they would bring to any team, regardless of the lineup around them, the ballpark they play in, or other contextual factors.

How is Wins Above Replacement used?

WAR is used by fans and journalists as a quick way to estimate a player’s total value, compared to a replacement player. 

It is important to note that in WAR, “replacement player” doesn’t refer to the player’s back-up on the roster, or a replacement superstar that a team could trade for. In this case, the “replacement player” is a theoretical idea, referring to the sort of AAA player that a team could call up to their roster for free.

Therefore, replacement level is quite low. A team of replacement-level players could be expected to have around a .294 winning percentage. Average MLB players, on the other hand, are quite valuable, usually rating around 2.0 WAR in a season.

WAR is also used after a player retires, in order to gain an understanding of their entire career. Hall of Fame debates often use WAR as a way of understanding whether a player is worthy of induction.

How to calculate Wins Above Replacement?

There are a few different ways to calculate Wins Above Replacement. Because WAR is not a stat like hits or walks, that corresponds to single game actions clearly laid out in the rule book, it is important for a WAR formula to have a framework that can be applied to every player in order to ensure consistent results.

On Baseball Reference, WAR for hitters is calculated from different component parts. Starting with hitters, WAR takes everything a player did as a batter, including hits, walks, strikeouts, and more, and uses a framework to calculate the player’s overall offensive contribution. It then does the same for the player’s defensive work (using the DRS framework) and baserunning. 

In addition to those, WAR includes an adjustment for the player’s position. This is because different positions have different offensive standards. For example, in 2024, catchers in the major league produced an OPS of .678, while DHs had an OPS of .742. A player with a .700 OPS would be an above average hitter as a catcher, but below average as a DH. Finally, the player is credited with the value of a replacement-level player, in order to set a league-wide baseline.

For pitchers, the process is the same, but the inputs are slightly different. Baseball Reference’s WAR starts with RA9. This stat is like ERA, but without the earned vs unearned run distinction. It then adjusts for the quality of opponents faced, the defense behind the pitcher, their role (starter or reliever), the ballparks they pitched in and, starting in 2020, any innings pitched in extra innings where the “ghost runner” now starts on second.

Wins Above Replacement Examples

In 2024, Shohei Ohtani’s WAR was calculated by starting with the WAR components. Here are the components and how the broke down:

  • Rbat, or the batting component of WAR = 74
  • Rfield, or the fielding component of WAR = 0
  • Rdp, an adjustment for avoiding grounding into double plays = 3
  • Rbaser, or the baserunning component of WAR = 10
  • Rpos, an adjustment for position = -16
  • Replacement level = 23

That gives Ohtani roughly 93 runs, although the number is lower than that due to rounding. It is generally accepted that 10 runs equal one win, so Ohtani’s WAR was 9.2.

The all-time greatest season by WAR was by Tim Keefe, who had 20.2 WAR in 1883. In the modern era, the best season by a pitcher was Dwight Gooden’s 13.3 in 1985. The best by a position player was Babe Ruth’s 14.1 in 1923 (Ruth did not pitch at all that season).

Career-wise, the most WAR in MLB history is 182.6, a record set by Babe Ruth. In the modern era, the record holder is Barry Bonds with 162.8 

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