What is FIP in Baseball?
Fielding Independent Pitching · Advanced
FIP (Fielding Independent Pitching) measures what a pitcher's ERA would look like if they were backed by average defense and average luck on balls in play. It is calculated using only the outcomes a pitcher fully controls — home runs allowed, walks issued, hit batters, and strikeouts — without any influence from the defense behind them or the randomness of batted ball outcomes.
Formula
FIP = (13 × HR + 3 × (BB + HBP) − 2 × SO) ÷ IP + FIP Constant
A pitcher who allows 25 HR, 40 BB, 5 HBP, and records 200 SO in 200 IP has: FIP = (13×25 + 3×45 − 2×200) / 200 + 3.10 = (325 + 135 − 400) / 200 + 3.10 = 60/200 + 3.10 = 0.30 + 3.10 = 3.40.
Benchmarks
| Level | FIP |
|---|---|
| Elite | < 3.00 |
| Excellent | 3.00–3.50 |
| Above Average | 3.50–4.00 |
| Average | 4.00–4.50 |
| Below Average | > 4.50 |
ALL-TIME CAREER FIP LEADERS
| Rank | Player | FIP |
|---|---|---|
| 1 | Rube Waddell | 2.63 |
| 2 | Jacob deGrom | 2.66 |
| 3 | Satchel Paige | 2.67 |
| 4 | Joe Williams | 2.68 |
| 5 | Ed Walsh | 2.71 |
| 6 | Mariano Rivera | 2.77 |
| 7 | Smoky Joe Wood | 2.79 |
| 8 | John Ward | 2.80 |
| 9 | Clayton Kershaw | 2.83 |
| 10 | Chris Sale | 2.86 |
BEST SINGLE-SEASON FIP IN MLB HISTORY
| Rank | Player | Year | Team | FIP |
|---|---|---|---|---|
| 1 | Pedro Martinez | 1999 | BOS | 1.36 |
| 2 | Dupee Shaw | 1884 | BSU | 1.54 |
| 3 | Corbin Burnes | 2021 | MIL | 1.56 |
| 4 | Clayton Kershaw | 2014 | LAD | 1.78 |
| 5 | Satchel Paige | 1934 | PC | 1.85 |
| 6 | Hugh Daily | 1884 | CHU | 1.90 |
| 7 | Jacob deGrom | 2018 | NYN | 1.92 |
| 8 | Charlie Sweeney | 1884 | SLU | 1.92 |
| 9 | Jim McCormick | 1884 | CNU | 1.95 |
| 10 | Clayton Kershaw | 2015 | LAD | 1.96 |
HISTORICAL CONTEXT
FIP was developed by Tom Tango, one of the leading figures in baseball analytics, and popularized on the website "The Book" and FanGraphs in the mid-2000s. It addressed a known limitation of ERA: that pitchers are only partially responsible for their ERA, since batted ball outcomes are heavily influenced by the defense behind them.
Research shows that FIP is more predictive of future ERA than past ERA itself, because it strips away the noise of defense and batted ball luck. A pitcher whose ERA is much higher than their FIP is often described as "unlucky" or "defense-dependent" and is considered likely to improve.
FIP- (FIP-minus) is a park- and era-adjusted version of FIP, like ERA+ but for FIP, scaled so 100 is league average and lower is better. xFIP replaces actual home runs with expected home runs (based on fly ball rate) to further stabilize the metric.
Critics note that FIP ignores a pitcher's ability to suppress hard contact on balls in play — a skill some pitchers demonstrably possess. More advanced metrics like SIERA (Skill-Interactive ERA) attempt to incorporate batted ball quality. Despite this, FIP remains the most widely used defense-independent pitching metric and appears on virtually every major baseball statistics platform.
ERA COMPARISON: HOW THE LEAGUE AVERAGE HAS SHIFTED
Because FIP uses an era-adjusted constant, league-average FIP mirrors league-average ERA closely. It is most useful for comparing individual pitchers within the same season rather than across eras.
| Era | Years | Lg Avg FIP (approx.) |
|---|---|---|
| Dead Ball Era | 1900–1919 | 2.89 |
| Live Ball Era | 1920–1941 | 4.14 |
| Post-WWII Era | 1942–1960 | 3.84 |
| Year of the Pitcher | 1961–1968 | 3.53 |
| Expansion Era | 1969–1988 | 3.78 |
| Steroid Era | 1989–2005 | 4.31 |
| Post-Steroid Era | 2006–2019 | 4.17 |
| Modern Era | 2020–2024 | 4.19 |
The FIP constant is recalibrated each season so league-average FIP equals league-average ERA. Use FIP to compare pitchers within the same season context, not across eras. Computed from Lahman historical MLB data.
FREQUENTLY ASKED QUESTIONS
What is FIP in baseball?
FIP (Fielding Independent Pitching) measures what a pitcher's ERA would look like if they were backed by average defense and average luck on balls in play. It is calculated using only the outcomes a pitcher fully controls — home runs allowed, walks issued, hit batters, and strikeouts — without any influence from the defense behind them or the randomness of batted ball outcomes.
How is FIP calculated?
FIP weights each event a pitcher controls by its run value: home runs (worth ~1.4 runs each, multiplied by 13 in the formula), walks and hit batters (~0.3 runs each, multiplied by 3), and strikeouts (~0.2 runs each, multiplied by −2). The FIP Constant (~3.10) is added to scale FIP to the same range as ERA for easy comparison.
What is a good FIP in baseball?
FIP is scaled to the same range as ERA. A FIP below 3.00 is elite; 3.00–3.50 is excellent; 3.50–4.00 is above average; 4.00–4.50 is average; above 4.50 is below average. A pitcher with a much lower ERA than FIP may be benefiting from good defense or lucky BABIP, and may regress. A pitcher with a much lower FIP than ERA may be unlucky and due for improvement.
What is the difference between ERA and FIP?
ERA counts all earned runs a pitcher allows, which includes batted balls that happen to fall for hits regardless of whether the pitcher had control over that outcome. FIP removes the defense and luck from the equation, measuring only strikeouts, walks, hit batters, and home runs — the outcomes the pitcher fully controls. FIP is generally more predictive of future performance than ERA.
What is xFIP and how does it differ from FIP?
xFIP (Expected FIP) replaces a pitcher's actual home run total with an expected home run total based on their fly ball rate and a league-average home-run-per-fly-ball rate. This makes xFIP even more stable than FIP by removing year-to-year fluctuations in HR/FB rate, which has a significant random component. xFIP is often used alongside FIP to identify pitchers whose home run rates are likely to regress.
EXPLORE MORE STATS
Pitching
ERA
Learn more →
Batting
OPS
Learn more →
Batting
AVG
Learn more →
Batting
HR
Learn more →
Batting
RBI
Learn more →
Advanced
WAR
Learn more →
Pitching
WHIP
Learn more →
Batting
SLG
Learn more →
Batting
OBP
Learn more →
Pitching
Wins
Learn more →
Pitching
SO
Learn more →
Batting
SB
Learn more →
Pitching
SV
Learn more →
Batting
BB
Learn more →
Pitching
K/9
Learn more →
Pitching
BB/9
Learn more →
Advanced
BABIP
Learn more →
Advanced
wOBA
Learn more →
Advanced
PIV
Learn more →