⚾FIP Calculator
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In 2010, sabermetrician Tom Tango introduced Fielding Independent Pitching (FIP) to a mainstream audience through FanGraphs, and the metric quickly reshaped how baseball evaluates pitchers. Before FIP, ERA reigned supreme — but ERA has a dirty secret: it penalizes pitchers for bad defense behind them and rewards them for good gloves they had nothing to do with. FIP strips all of that away. FIP measures only the outcomes a pitcher directly controls: strikeouts, walks, hit-by-pitches, and home runs allowed. Everything else — singles, doubles, groundouts, flyouts — involves fielders, batters, and a healthy dose of luck. FIP ignores those balls in play entirely and asks a simple question: based solely on true outcomes, how good was this pitcher? The metric is scaled to look like ERA, making it immediately intuitive. A league-average FIP is typically around 4.00 in recent seasons, though it shifts with run-scoring environments. An elite starter like Jacob deGrom posted a 1.08 FIP in 2021 — one of the lowest ever recorded — while his ERA was a still-excellent 1.08 as well, but in other seasons his FIP has dramatically outpaced his ERA, revealing how much better he was than his surface stats suggested. Scouts and front offices use FIP to identify pitchers who are outperforming or underperforming their true talent level. A pitcher with a 3.20 ERA but a 4.50 FIP is likely getting lucky — his ERA will probably rise. Conversely, a pitcher with a 4.80 ERA but a 3.30 FIP is probably pitching better than his record shows and is a buy candidate in trade markets. FIP is not without limitations. It assumes all home runs are equal (they're not, based on park factors), and it doesn't account for sequencing, pitch framing, or how a pitcher induces weak contact. For those reasons, analysts often pair FIP with xFIP, SIERA, or Statcast metrics. Still, FIP remains one of the most powerful and widely adopted pitcher evaluation tools in the sport.
FIP = ((13 × HR) + (3 × (BB + HBP)) - (2 × K)) / IP + FIP Constant
Where:
- HR = Home runs allowed
- BB = Walks (base on balls)
- HBP = Hit batters
- K = Strikeouts
- IP = Innings pitched
- FIP Constant = A value (typically ~3.10 to 3.20) added each season to scale FIP to ERA
Worked Example (Jacob deGrom, 2021 approximation):
HR=7, BB=21, HBP=3, K=146, IP=92, Constant=3.17
FIP = ((13×7) + (3×(21+3)) - (2×146)) / 92 + 3.17
= (91 + 72 - 292) / 92 + 3.17
= (-129) / 92 + 3.17
= -1.402 + 3.17
= 1.77 FIP- 1Collect the pitcher's season totals for home runs allowed (HR), walks (BB), hit batters (HBP), strikeouts (K), and innings pitched (IP) from a source like Baseball-Reference or FanGraphs.
- 2Multiply home runs by 13, because home runs are the most damaging true outcome — every HR scores at least one run and cannot be 'saved' by defense.
- 3Multiply the sum of walks and hit batters by 3, reflecting the run value of putting a batter on base via true pitcher error.
- 4Multiply strikeouts by 2 and subtract that from the previous totals, since strikeouts prevent base runners and are entirely pitcher-controlled.
- 5Divide the resulting numerator by innings pitched to normalize the rate across different workloads.
- 6Add the FIP constant (published annually by FanGraphs) to align the scale with league ERA, making FIP directly comparable to ERA across different seasons.
- 7Interpret the result: below 3.00 is elite, 3.00–3.75 is above average, 3.75–4.50 is average, 4.50–5.25 is below average, and above 5.25 is poor.
deGrom's 2021 FIP was historically low, reflecting his dominant strikeout rate and near-zero home run rate. His ERA matched his FIP closely, confirming genuine dominance rather than luck.
A mid-rotation starter with decent strikeouts but average walk and homer rates lands right at the league-average FIP band, suggesting a replacement-level to slightly above-average pitcher.
High strikeout rates in short stints drive down FIP dramatically. This reliever profile matches a typical late-inning setup man or closer with swing-and-miss stuff.
If this pitcher's ERA were 4.80, it would suggest bad luck on balls in play or poor defensive support — a strong buy-low candidate for GM trade discussions.
Primary care physicians and internists use Fip Calculator during routine clinical assessments to screen patients, establish baselines for longitudinal monitoring, and identify individuals who may need referral to specialists for further diagnostic evaluation or therapeutic intervention.
Fantasy baseball analysts use FIP to predict ERA regression — a pitcher with a 3.00 ERA and 4.50 FIP is a strong sell candidate heading into the second half of the season.
Hospital clinical pharmacists apply Fip Calculator to verify drug dosing calculations, particularly for medications with narrow therapeutic indices like warfarin, aminoglycosides, and chemotherapy agents where patient-specific factors such as renal function and body weight critically affect safe dosing ranges.
Public health epidemiologists use Fip Calculator in population-level screening programs to calculate disease prevalence, assess screening test sensitivity and specificity, and determine the number needed to screen to detect one case in various demographic subgroups.
Pediatric versus adult reference ranges
In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in fip calculatorulator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
Pregnancy and hormonal variations
In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in fip calculatorulator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
Extreme body composition
In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in fip calculatorulator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
| FIP Range | Rating | Percentile | Example Players |
|---|---|---|---|
| < 2.75 | Historic / Elite | Top 1% | deGrom 2021, Kershaw 2014 |
| 2.75 – 3.25 | Elite | Top 5–10% | Verlander, Scherzer, Cole |
| 3.25 – 3.75 | Above Average | Top 25% | Fried, Gausman, Strider |
| 3.75 – 4.25 | Average | 50th percentile | Typical #3–4 starters |
| 4.25 – 5.00 | Below Average | Bottom 30% | Back-end rotation arms |
| > 5.00 | Poor | Bottom 10% | Replacement-level pitchers |
What is a good FIP for a starting pitcher?
Fip Calculator is a specialized calculation tool designed to help users compute and analyze key metrics in the health and medical domain. It takes specific numeric inputs — typically drawn from real-world data such as measurements, rates, or quantities — and applies a validated mathematical formula to produce actionable results. The tool is valuable because it eliminates manual calculation errors, provides instant feedback when exploring different scenarios, and serves as both a decision-support instrument for professionals and a learning aid for students studying the underlying principles.
What is the FIP constant and why does it change each year?
Fip Calculator is a specialized calculation tool designed to help users compute and analyze key metrics in the health and medical domain. It takes specific numeric inputs — typically drawn from real-world data such as measurements, rates, or quantities — and applies a validated mathematical formula to produce actionable results. The tool is valuable because it eliminates manual calculation errors, provides instant feedback when exploring different scenarios, and serves as both a decision-support instrument for professionals and a learning aid for students studying the underlying principles.
Is FIP better than ERA for evaluating pitchers?
In the context of Fip Calculator, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of health and medical practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
Can a pitcher consistently outperform their FIP?
In the context of Fip Calculator, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of health and medical practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
Does FIP work for relievers?
In the context of Fip Calculator, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of health and medical practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
Why does FIP weight home runs at 13?
In the context of Fip Calculator, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of health and medical practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
How does FIP relate to xFIP?
In the context of Fip Calculator, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of health and medical practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
专业提示
Always compare a pitcher's FIP to their xFIP and SIERA simultaneously. If all three agree, you have high confidence in the assessment. If FIP is much lower than xFIP, the pitcher is likely getting lucky on home runs — a red flag for regression.
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In 2021, Jacob deGrom's FIP was so low (around 1.08 in some stretches) that he was on pace to shatter records, yet the Mets failed to capitalize on his starts. He had a 7-2 record despite arguably the greatest sustained pitching stretch in modern history — a perfect illustration of how FIP exposes run support luck that ERA cannot.