Wins Above Replacement (WAR) Understood: What is WAR? What does WAR mean? How is WAR used?

~ From the Braintrust ~

Wins Above Replacement (WAR) has become widely used in the world of baseball, but what exactly does the term mean? How is WAR determined?

As Piper Slowinski shares with FanGraphs, WAR is a statistic used to “summarize a player’s total contributions to their team in one statistic.”

Baseball owners have proposed using WAR in determining salary arbitration levels, a concept the players have reportedly turned down.

Wins Above Replacement (WAR) is an attempt by the sabermetric baseball community to summarize a player’s total contributions to their team in one statistic. You should always use more than one metric at a time when evaluating players, but WAR is all-inclusive and provides a useful reference point for comparing players. WAR offers an estimate to answer the question, “If this player got injured and their team had to replace them with a freely available minor leaguer or a AAAA player from their bench, how much value would the team be losing?” This value is expressed in a wins format, so we could say that Player X is worth +6.3 wins to their team while Player Y is only worth +3.5 wins, which means it is highly likely that Player X has been more valuable than Player Y. – Piper Slowinski,

All About WAR

● For Position Players

● For Pitchers


Calculating WAR, especially for position players, is simpler than you’d think. If you want the detailed version with the precise steps and formulas, head to our page on Position Player WAR or Pitcher WAR. The short answer, though, is as follows:

● Position players – To calculate WAR for position players you want to take their Batting Runs, Base Running Runs, and Fielding Runs above average and then add in a positional adjustment, a small adjustment for their league, and then add in replacement runs so that we are comparing their performance to replacement level rather than the average player. After that, you simply take that sum and divide it by the runs per win value of that season to find WAR. The simple equation looks something like this:

WAR = (Batting Runs + Base Running Runs +Fielding Runs + Positional Adjustment + League Adjustment +Replacement Runs) / (Runs Per Win)

● Pitchers – While position player WAR is based on Batting Runs and Fielding Runs, pitching WAR uses FIP (with infield fly balls), adjusted for park, and scaled to how many innings the pitcher threw. FIP is translated into runs, converted to represent value above replacement level, and is then converted from runs to wins. This is a slightly more complicated process than for position players, so you should click over to the pitcher WAR page if you want the details.

Why WAR:

WAR is trying to answer the time-honored question: How valuable is each player to his team? Baseball is the sum of many different parts and players can help their teams win through hitting, base running, defensive play, or pitching. Comparing two players offensively is useful, but it discounts the potential contribution a player can make by saving runs on defense. WAR is a simple attempt to combine a player’s total contribution into a single value.

How to Use WAR:

For position players and starting pitchers, here is a good rule-of-thumb chart:

Scrub 0-1 WAR
Role Player 1-2 WAR
Solid Starter 2-3 WAR
Good Player 3-4 WAR
All-Star 4-5 WAR
Superstar 5-6 WAR

Also, here’s a fun breakdown of all the players in baseball in 2010, courtesy of Justin Bopp from Beyond the Boxscore.

Links for Further Reading:

WAR for Position Players – FanGraphs

WAR for Pitchers – FanGraphs

Intro to WAR – Big League Stew

Background on WAR – Offense (Note that these are slightly outdated. They have great info, but some calculations have changed.)

Background on WAR – Pitching (Note that these are slightly outdated. They have great info, but some calculations have changed.)

Common Misconceptions – The Book Blog

Simple WAR Calculator – Wahoo’s On First

wOBA to WAR Conversion – Beyond the Boxscore

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David Keech
Author: David Keech

David Keech is a math teacher in Wisconsin Rapids and public address announcer for Abbotsord High School. He officiates basketball, baseball, and softball in central Wisconsin. He has reported on amateur sports since 2011, known as 'KeechDaVoice.' David can be reached at [email protected]