FIP Calculator (Fielding Independent Pitching)

FIP is an advanced pitching statistic that measures a pitcher's effectiveness based only on outcomes they directly control: strikeouts, walks, hit-by-pitches, and home runs. It removes the influence of fielding and luck on balls in play, providing a cleaner picture of true pitching skill. FIP is scaled to look like ERA for easy comparison.

The FIP formula is: FIP = ((13 × HR) + (3 × (BB − IBB + HBP)) − (2 × SO)) / IP + FIP Constant. Each event is weighted by its average run value — home runs at 13, walks and HBP at 3, and strikeouts at −2. The FIP constant adjusts the final value to the same scale as ERA.

The FIP constant is added to align FIP with ERA on the same numerical scale. It's calculated using league-wide averages: FIP Constant = lgERA − ((13 × lgHR) + (3 × (lgBB + lgHBP)) − (2 × lgSO)) / lgIP. The standard constant is approximately 3.10, though it varies slightly each season based on league run environment.

Lower FIP scores indicate better performance. An FIP below 3.00 is considered elite, 3.00–3.75 is above average, 3.75–4.25 is roughly average, 4.25–5.00 is below average, and anything above 5.00 is poor. The best single-season FIPs in MLB history have been below 2.00.

ERA can be heavily influenced by the quality of a team's defense and by luck on balls in play. FIP strips those external factors out, focusing only on what the pitcher controls. Over a full season, FIP tends to be a better predictor of future ERA than ERA itself, making it a more reliable indicator of true pitching talent.

FIP uses a pitcher's actual home runs allowed, while xFIP (Expected FIP) replaces actual HR with an expected HR total based on the pitcher's fly ball rate and league-average HR/FB ratio. xFIP helps further normalize for whether a pitcher was unusually lucky or unlucky in how many fly balls left the park.

It depends on the version of FIP you're using. Many modern implementations subtract intentional walks from total walks, since IBBs are a strategic decision by the manager rather than a reflection of pitcher control. Our calculator lets you enter IBB separately and excludes them from the walk count used in the formula.

FIP becomes more reliable as sample size grows. As a rough guideline, at least 30–50 innings pitched are needed to draw meaningful conclusions, and 150+ innings provides a highly stable estimate. For short stints or relief appearances, FIP should be interpreted with caution due to small-sample variability.