About this tool
The FIP Calculator computes Fielding Independent Pitching, a sabermetric statistic that measures a pitcher on only the outcomes they most directly control — strikeouts, walks, hit-by-pitches and home runs — while removing the influence of defense and batted-ball luck. It is deliberately scaled to look like ERA so the two can be compared side by side.
The formula is FIP = ((13·HR) + (3·(BB + HBP)) − (2·K)) / IP + constant. The constant is a league-wide value, added each season so that league-average FIP equals league-average ERA; it typically lands between about 3.0 and 3.2 and defaults to 3.10 here, but you can edit it to match a specific season or league. Innings pitched are entered in baseball thirds notation (for example 180.2 = 180 innings and 2 outs) and converted correctly before dividing.
Everything is computed locally in your browser, so nothing you enter is transmitted. When a pitcher's FIP is well below their ERA it suggests the results were worse than the underlying performance — often poor defense or bad luck on balls in play — and vice versa. If you supply the actual ERA, the tool also reports the ERA − FIP gap so you can gauge how much a pitcher may regress toward their fielding-independent line.