About the FIP Calculator
This FIP calculator works out fielding independent pitching, the sabermetric stat that judges a pitcher only on the outcomes he controls most directly: home runs, walks, hit-by-pitches and strikeouts. Everything that happens once the ball is put in play, including the quality of the defense behind him and the luck of where grounders and bloopers land, is left out.
Enter the pitcher’s line and innings pitched (box-score notation such as 172.1 works), and the calculator returns FIP on the familiar ERA scale along with HR/9, BB/9 and K/9. Add his actual ERA to see the ERA − FIP gap, which analysts use as a quick signal that a pitcher has been lucky or unlucky and may regress.
The FIP constant puts the result on the same scale as league ERA and changes slightly every season. FanGraphs notes it usually sits around 3.10; change it if you want to match a specific league and year, such as a college or minor league season.
With the default inputs, the fip is 3.48. Change any value above to recalculate instantly.
How to use the fip calculator
- 1Enter home runs, walks, hit batters and strikeouts from the pitcher’s stat line.
- 2Enter innings pitched as the box score shows them (e.g. 172.1).
- 3Leave the constant at 3.10 or enter the exact value for the season you are studying.
- 4Add the pitcher’s ERA to see the ERA − FIP gap.
- 5Read FIP like an ERA: lower is better, around 4.20 is average.
Formula and method
FIP weights each fielding-independent event by its approximate run value: a home run costs about 13 times as much per inning as the baseline, a walk or hit batter about 3, and a strikeout saves about 2. The weighted sum is divided by innings pitched (in true thirds, so 172.1 = 172⅓) to get a per-inning figure.
The constant C is added so that league-average FIP equals league-average ERA for that season. It is computed each year as league ERA minus the league’s raw FIP and usually lands near 3.10 in MLB. Because the constant is the same for every pitcher in a season, it never changes rankings — only the scale.
- HR
- Home runs allowed
- BB
- Walks allowed (including intentional)
- HBP
- Batters hit by pitch
- K
- Strikeouts
- IP
- Innings pitched (outs ÷ 3)
- C
- FIP constant for the league and season (≈ 3.10)
Worked examples
Strikeout ace over 180 innings
13 × 20 = 260, plus 3 × (50 + 6) = 168, minus 2 × 180 = 360 gives 68. Dividing by 180 innings gives 0.378, and adding the 3.10 constant makes FIP 3.48 — almost exactly his 3.60 ERA.
Lucky ERA in 150.2 innings
150.2 innings is 150⅔. The weighted events are 325 + 180 − 240 = 265, and 265 ÷ 150.667 = 1.759, so FIP = 4.86. His 3.20 ERA is 1.66 runs better than FIP, a classic regression warning.
Relief season with a custom constant
13 × 4 + 3 × 22 − 2 × 80 = 52 + 66 − 160 = −42. Over 60 innings that is −0.70 runs per inning, and with a 3.20 constant the FIP is 2.50 — elite for a reliever.
Frequently asked questions
What does FIP stand for in baseball?+
FIP means fielding independent pitching. It estimates what a pitcher’s ERA should have been based only on strikeouts, walks, hit batters and home runs — the outcomes that do not depend on the fielders behind him.
What is a good FIP?+
FanGraphs’ rule of thumb rates about 3.20 as excellent, 3.80 as above average, 4.20 as average, 4.70 as poor and 5.00 or higher as awful. Exact thresholds move with the league run environment each year.
Why is FIP different from ERA?+
ERA counts every earned run, including runs that score because of weak defense, unlucky bloop hits or bullpen collapses. FIP ignores balls in play, so a big gap between the two usually signals luck or defense effects that tend to even out.
What is the FIP constant?+
It is league ERA minus the league’s raw FIP for the season, which puts FIP on the same scale as ERA. FanGraphs notes it is generally around 3.10, and it is the same for every pitcher in a given league-season.
Is FIP better than ERA for predicting the future?+
For predicting a pitcher’s next-season ERA, FIP is usually more reliable than past ERA because strikeout, walk and home-run rates are more stable from year to year than results on balls in play.
What is xFIP?+
xFIP replaces a pitcher’s actual home runs with the number expected from his fly balls at the league-average home-run-per-fly-ball rate, removing home-run luck as well. It needs fly-ball data, which this calculator does not use.