FIP Calculator (Fielding Independent Pitching)

Enter a pitcher's home runs, walks, hit-by-pitch, strikeouts, and innings pitched to compute FIP — an ERA-scale metric of the outcomes a pitcher controls independent of fielding.

Quick Facts

Formula
FIP = (13×HR + 3×(BB+HBP) − 2×K) ÷ IP + constant
Scaled to ERA via a season constant (~3.10). Lower is better; ~3.20 is excellent, ~4.20 is average.

Your Results

Calculated
FIP
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ERA-scale, defense-independent
Raw FIP core
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Before adding the constant
Rating
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Where this lands vs MLB norms

Ready

Enter the pitcher's stat line and press Calculate.

About Fielding Independent Pitching (FIP)

Fielding Independent Pitching (FIP) is a sabermetric statistic that estimates a pitcher's run prevention using only the outcomes the pitcher controls almost entirely on his own: home runs, walks, hit batsmen, and strikeouts. Everything that happens once a ball is put in play — a diving catch, a booted grounder, a bloop that finds grass — depends heavily on the defense behind the pitcher and on luck, so FIP deliberately ignores those events. It was popularized by Tom Tango and is a standard column on sites like FanGraphs.

The FIP formula

The calculator uses the standard definition:

FIP = (13 × HR + 3 × (BB + HBP) − 2 × K) ÷ IP + FIP constant

  • HR — home runs allowed, weighted 13 because home runs are the most damaging event a pitcher fully owns.
  • BB + HBP — walks plus hit-by-pitch (free baserunners), weighted 3.
  • K — strikeouts, subtracted with a weight of 2 because a strikeout is a guaranteed out that never involves the defense.
  • IP — innings pitched (use decimals: ⅓ inning = .33, ⅔ inning = .67, not the .1/.2 box-score shorthand).
  • FIP constant — a per-season adjustment (roughly 3.10 in a typical MLB year) that shifts the whole scale so that league-average FIP equals league-average ERA. It changes slightly every year with run-scoring environment.

Why FIP instead of ERA

ERA counts every earned run a pitcher allows, but a large share of those runs turn on defense and sequencing luck that the pitcher cannot repeat. FIP strips that noise out, so it tends to predict a pitcher's next season ERA better than his current ERA does. When a pitcher's ERA sits well above his FIP, he has often been unlucky or poorly supported by his defense and may improve; when ERA sits well below FIP, he has likely been lucky and may regress.

Reference points on the ERA scale

Because FIP is deliberately scaled to look like ERA, the same rules of thumb apply. As a rough guide for a full MLB season:

  • ~3.20 or below — excellent, ace-level.
  • ~3.50 — very good / above average.
  • ~4.20 — roughly league average.
  • ~4.80 or above — below average.

Worked example: a starter with 18 HR, 45 BB, 6 HBP, 180 K over 190 IP and a 3.10 constant has a core of (13×18 + 3×51 − 2×180) ÷ 190 = (234 + 153 − 360) ÷ 190 = 27 ÷ 190 ≈ 0.142, so FIP ≈ 0.14 + 3.10 = 3.24 — a strong, above-average season.

Frequently Asked Questions

What is a good FIP?
On the ERA scale, a FIP around 3.20 or lower is excellent (ace territory), roughly 3.50 is very good, about 4.20 is league average, and 4.80 or higher is below average. Because the FIP constant re-centers each season, "average" always lands near the league's average ERA for that year.
What is the FIP constant and where do I get it?
The FIP constant is calculated each season as league ERA minus the league's raw FIP core, so that league-average FIP equals league-average ERA. It is typically near 3.10 but shifts with the run environment. FanGraphs publishes the exact yearly constant; if you don't have it, 3.10 is a reasonable default for a modern MLB season.
How do I enter innings pitched correctly?
Use true decimals, not box-score notation. One out is one-third of an inning, so 190⅔ innings is entered as 190.67, and 190⅓ as 190.33 — not 190.2 or 190.1. Using the .1/.2 shorthand will make the per-inning division slightly wrong.
Why does my FIP differ from ERA for the same pitcher?
FIP ignores balls in play, so defense, ballpark, and batted-ball luck don't affect it. A pitcher with a strong defense or good luck will usually have an ERA lower than his FIP; a pitcher with a poor defense or bad luck will have an ERA higher than his FIP. The gap is exactly the signal FIP is designed to expose.
What are FIP's limitations?
FIP assumes a pitcher has little control over balls in play, which is mostly but not entirely true — some pitchers consistently suppress hard contact or home runs. It also treats all home runs equally and can be volatile in small samples because home runs are relatively rare. For pitchers with unusual batted-ball profiles, metrics like xFIP or SIERA can complement it.

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