xFIP (Expected FIP) replaces a pitcher's actual home run total with an expected home run total based on fly ball rate. Since HR/FB rates fluctuate with luck, xFIP is a better predictor of future ERA than FIP. Expected HR = Fly Balls × 0.105 (the historical league-average HR/FB rate). xFIP is generally considered a better future ERA predictor than FIP itself.

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Baseball FIP Calculator

FIP, xFIP & FIP−ERA difference — defense-independent pitching metrics

Pitcher Stats

Enter pitcher game log or season totals

Innings Pitched format: Use X.Y where Y is outs (0, 1, or 2). Example: 7.2 = 7 innings + 2 outs = 7.667 decimal innings.

Innings Pitched (IP)

Home Runs (HR)

Walks (BB)

Hit Batters (HBP)

Strikeouts (K)

Fly Balls (FB) for xFIP calculation

FIP Constant scales FIP to ERA; default 3.10

Actual ERA (optional) to show FIP−ERA difference

Formulas Quick Reference

FIP

((HR×13) + (BB+HBP)×3 − K×2) ÷ IP + C

xFIP

Same as FIP but xHR replaces HR
xHR = FB × 0.105

What is FIP in Baseball?

FIP (Fielding Independent Pitching) is a sabermetric statistic introduced by Tom Tango that measures a pitcher's effectiveness based solely on the three outcomes the pitcher directly controls: home runs allowed, walks issued (including hit batters), and strikeouts recorded. All other batted-ball outcomes — singles, doubles, groundouts — are influenced heavily by the defense behind the pitcher and are therefore excluded.

FIP is scaled to look like ERA, using a "FIP constant" derived from the league's seasonal averages, so a FIP of 3.45 is interpreted exactly like an ERA of 3.45: it represents the number of runs per nine innings a pitcher would allow if their defense were perfectly average.

FIP Formula Explained

The full FIP formula is:

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

The coefficients reflect each event's historical run value:

HR × 13 — Home runs are extremely costly (average ~1.4 runs per HR in context).
(BB + HBP) × 3 — Walks and hit batters put runners on base; each costs roughly 0.33 runs.
K × 2 (subtracted) — Strikeouts prevent baserunners and double-play scenarios; each saves ~0.22 runs.
FIP Constant (~3.10) — Added so the FIP scale matches the ERA scale for the given season.

Worked example: A pitcher throws 180 IP, allows 20 HR, 60 BB, 5 HBP, records 200 K, FIP constant = 3.10.

Numerator = (20×13) + (60+5)×3 − 200×2 = 260 + 195 − 400 = 55
FIP = 55 ÷ 180 + 3.10 = 0.306 + 3.10 = 3.41

FIP vs ERA — Why FIP is More Predictive

ERA is influenced by many factors a pitcher cannot control: fielder errors, positioning, range of outfielders, defensive shifts, stadium dimensions, and even sequencing of hits. A pitcher can allow a leadoff walk and then give up a bases-clearing double — two events — or allow four consecutive singles for the same result. ERA blames the pitcher equally in both cases, even though the bloop hits behind a diving second baseman were not his fault.

Research by Tom Tango and others has demonstrated that FIP is a significantly better predictor of a pitcher's ERA in the following season than the pitcher's ERA in the current season. This is because ERA contains substantial "noise" from defense and luck, whereas FIP strips that noise away. In short, FIP tells you what a pitcher earned, while ERA tells you what the scorecard shows.

FIP Benchmarks

FIP Range	Rating	Description
< 2.90	Elite	True ace, Cy Young contender
2.90 – 3.50	Excellent	No. 1 / 2 starter, All-Star caliber
3.50 – 4.20	Average	Solid rotation piece, league average
> 4.20	Poor	Below average, high regression risk

xFIP: One Step Further

Even FIP can be influenced by luck — specifically, the rate at which fly balls leave the park. League-average HR/FB rate is approximately 10.5%, but it can swing 3–5% in either direction for individual pitchers in a given season. xFIP normalizes this by replacing the pitcher's actual HR with an expected HR based on their fly ball total: xHR = Fly Balls × 0.105.

xFIP is the most reliable short-term ERA predictor available. However, a small subset of pitchers — those who genuinely suppress hard contact or have "stuff" that limits fly-ball distances — may consistently outperform their xFIP.

Frequently Asked Questions

What is FIP in baseball?

FIP (Fielding Independent Pitching) is a sabermetric pitching statistic that measures performance based only on outcomes a pitcher directly controls: home runs, walks, hit batters, and strikeouts. It ignores all batted-ball outcomes (which are heavily influenced by defense) and is scaled to match the ERA scale using a FIP constant so the two numbers can be directly compared.

How is FIP calculated?

FIP = ((HR × 13) + (BB + HBP) × 3 − K × 2) ÷ IP + FIP_Constant. The FIP constant is typically around 3.10 and is recalculated each season to keep FIP on the same scale as ERA. Home runs receive the heaviest weight (13) because they directly produce runs. Strikeouts reduce FIP (coefficient −2) while walks and hit batters increase it (+3 each).

What is xFIP?

xFIP (Expected FIP) takes FIP one step further by replacing a pitcher's actual home run total with an expected home run total based on their fly ball count. Expected HR = Fly Balls × 0.105 (the historical league-average HR/FB rate of ~10.5%). Because a pitcher's actual HR/FB rate fluctuates significantly year to year due to luck, xFIP is an even better predictor of future performance than FIP.

Is FIP better than ERA for evaluating pitchers?

For most pitchers, FIP is a better indicator of true pitching skill than ERA because it removes the influence of defense and batted-ball luck. ERA reflects what actually happened on the field (including unearned runs from errors, etc.); FIP isolates what the pitcher was responsible for. However, pitchers who consistently induce weak contact or grounders may sustainably outperform their FIP — in those cases, metrics like xFIP or SIERA may give a more complete picture.

What does a negative FIP minus ERA value mean?

When FIP − ERA is negative, it means the pitcher's FIP is lower than their ERA — they performed better by the defense-independent measure than the scoreboard shows. This is often caused by poor defense or bad sequencing luck (many singles bunched together). Expect ERA regression toward FIP going forward. When FIP − ERA is positive, the pitcher's ERA is lower than FIP, meaning they benefited from great defense or lucky batted-ball outcomes. Their ERA may worsen as luck normalizes.