The fWAR vs. bWAR Breakdown
One of the biggest arguments in the baseball world is the preference over bWAR and WAR. While both sites (Baseball Reference and Fangraphs) attempt to summarize a player’s total value into a single number, they often arrive at different conclusions because they are using slightly different equations.
The Core Difference: Results vs. Skills
The biggest divide between the two systems. fWAR (FanGraphs) and bWAR (Baseball-Reference), comes down to how they evaluate pitchers and defenders.
bWAR: This model starts with runs allowed (RA9). It asks: “How many runs did this pitcher actually give up?” It then adjusts for the quality of the opponents, the ballparks, and the defense playing behind them. bWAR uses actual runs allowed regardless of how they happened, whereas fWAR focuses more on simply what the pitcher controls.
fWAR: This model is built on Fielding Independent Pitching (FIP). It focuses on outcomes the pitcher controls most directly: strikeouts, walks, and home runs. It is designed to be “fielding-independent” and is often seen as a better indicator of true talent or future performance.
Why Hitter WAR Differs
For position players, the two systems generally align more closely than they do for pitchers because they use similar “linear weights” for hitting. However, gaps still occur, primarily due to different defensive inputs:
While fWAR uses OAA to measure range, these stats are often rolled into Statcast’s broader Fielding Run Value (FRV), which provides a comprehensive look at a player’s total defensive impact by also accounting for arm strength and catching metrics. FRV also includes “Cather Framing,” which is the ability of a catcher to turn balls into strikes. It will be interesting to see how ABS affects this.
bWAR uses the DRS (Defensive Runs Saved) family of inputs.
A recent example that shows the gap for a hitter would be Patrick Bailey in 2024.
fWAR: 4.3 | bWAR: 1.8
Patrick Bailey is widely considered the best defensive catcher in baseball by Statcast. Because fWAR incorporates his elite pitch framing and Statcast framing runs, he is valued as a borderline All-Star. However, in bWAR, which focuses more on traditional results, sees a league-average player.
Some Other Examples
To truly understand how these systems diverge, it helps to look at specific seasons where the numbers told two different stories.
Sandy Alcantara (2022)
In 2022, Sandy Alcantara’s season became the canonical example of the “innings-eater bonus.”
bWAR: 8.0 (Led all of MLB)
fWAR: 5.9
Alcantara’s 2.28 ERA and MLB-leading 228.2 innings were massive and might be the last time we see an ace pitch that deep in so many games. Because bWAR is built on actual run prevention (RA9), it heavily rewarded his massive workload and his ability to carry a game into the 8th or 9th inning (he threw 6 complete games that year). However, fWAR was more conservative because his 2.99 FIP wasn’t quite as dominant as his ERA (he was 8th that year in FIP).
Blake Snell (2023)
Blake Snell’s 2023 season was a “run prevention monster” that faced “FIP warnings.”
bWAR: 6.5
fWAR: 4.1
Snell became the first pitcher since 1913 to lead the Majors in both ERA (2.25) and Walks (99) in the same season. bWAR rewarded him for the results: he allowed the fewest hits per nine innings (5.8 H/9) and the lowest opponent batting average (.180) in baseball. Essentially, bWAR saw a pitcher who was impossible to hit and “pitched out of trouble” every time he walked someone.
However, fWAR was significantly lower because its FIP-based formula treats walks as a “deadly sin.” Because he walked 13.3% of the batters he faced, the model viewed him as a pitcher dancing on the edge of a cliff. While he won the Cy Young, fWAR remained skeptical, viewing his season as a high-wire act sustained by an unsustainable 86.7% strand rate.
Cal Raleigh (2025)
In 2025, Cal Raleigh put together arguably the greatest offensive season by a catcher in MLB history, shattering records with 60 home runs and leading the Mariners to their first division title in over two decades.
bWAR: 7.4
fWAR: 9.1
While bWAR still sees an MVP-level season, it is nearly two wins lower because it does not incorporate framing runs. Additionally, bWAR’s DRS (Defensive Runs Saved) metric was more conservative on his overall defensive impact compared to the Statcast metrics used by fWAR. Fangraphs places high value on his elite pitch framing (93rd percentile) and his power output. Still was not enough to catch Judge who had 10.1 fWAR.
Which One Should You Use?
For Hall of Fame Debates: bWAR is the most commonly cited historical leaderboard in Hall of Fame debates
For Predicting Next Season: Lean toward fWAR. Its focus on FIP-based components and Statcast OAA is more informative for forecasting “what should happen next.”
For Award Debates: Use both.
Personally, I always reference bWAR when I am writing blogs or tweeting. Only recently have MLB fans started going after me for it. However, I will not change.
Great read. Always wondered about the difference.