FIP Calculator

162⅔ innings with 201 strikeouts, 46 walks, 2 hit batters and 20 home runs make a FIP of 3.11

FIP (Fielding Independent Pitching) is an ERA-style number built only from the four things a pitcher decides on his own: strikeouts, walks, hit batters and home runs. FanGraphs describes it as a measure of what a pitcher's ERA would look like if he had experienced league-average results on balls in play and league-average timing. The formula is (13 × home runs + 3 × (walks + hit batters) − 2 × strikeouts) ÷ innings pitched + a constant, and the constant only moves the result onto the same scale as ERA.

Take Jacob deGrom of the Texas Rangers in 2026. The parts are 13 × 20 = 260, 3 × (46 + 2) = 144 and 2 × 201 = 402, so the top of the fraction is 260 + 144 − 402 = 2. His 162.2 innings are 162⅔ innings, so 2 ÷ 162⅔ = 0.012, and adding the 2026 MLB constant of 3.093 gives a FIP of 3.11. His ERA that season was 4.20, which is 1.09 higher. In other words, his strikeouts, walks and home runs pointed to about a run less than he actually allowed. Among the 46 qualified MLB pitchers, none of the other 17 whose ERA was above their FIP had a bigger gap. The 2026 MLB average is 4.17, and counting deGrom himself, 10 of the 46 had a FIP as low as his 3.11 or lower.

Why look at FIP next to ERA

ERA counts every run that scored while the pitcher was on the mound. That makes it depend on how well the defense behind him played and on the order in which hits happened. FanGraphs gives an example: with two outs, a single, a single, a home run and an out score three runs, while a home run, a single, a single and an out score only one, although the four events are identical. FIP strips out defense, luck and sequencing and keeps only the pitcher's own results. That is why it is useful to read it next to ERA in cases like these:

• A pitcher's ERA looks oddly high or low midseason, and you want to know whether skill changed or luck did.
• You want to compare pitchers who work in front of strong and weak defenses on one scale.
• You are guessing at next season's ERA: FanGraphs says that if you had to bet on ERA or FIP, FIP is the better bet.
• You are reading WAR: FanGraphs' version of WAR for pitchers is based on FIP rather than on ERA.

How to use the calculator

1. Pick the league to compare with at the top (MLB, KBO or NPB). The FIP constant box fills with that league's 2026 regular-season constant. MLB is selected by default.
2. Enter innings, strikeouts, walks, hit batters and home runs. Type innings as printed in the box score, like 162.1, and join several games with a plus sign, like 6.2+7+5.1. If you leave the hit-batter box empty, it counts as 0.
3. If you know the ERA, enter it too. The result strip shows ERA − FIP, and the chart draws this line from ERA down (or up) to FIP.
4. You can also load a 2026 qualified pitcher and compare a real player. A loaded pitcher is left out of his own rank and counts.
5. For a record from another season or league, type that constant into the FIP constant box. The constants table below also has the 2025 regular-season values.

How FIP is calculated

FanGraphs Library and the MLB glossary use the same formula. According to FanGraphs, the weights for home runs, walks and hit batters, and strikeouts come from the relative values of those events for run prevention.

• FIP = (13 × HR + 3 × (BB + HBP) − 2 × K) ÷ IP + constant
• IP = outs ÷ 3 (162.2 innings = 162⅔ innings = 488 outs)
• Constant = league ERA − (13 × league HR + 3 × (league BB + league HBP) − 2 × league K) ÷ league IP

Dividing by 162.2 as if it were a decimal can throw the result off. The calculator converts innings into outs before dividing and rounds only at the end, to two decimals. The tug-of-war picture under the result draws the same arithmetic: it starts at the constant, strikeouts pull it to the left, and walks, hit batters and home runs push it to the right. Where it ends is the FIP.

FIP constants by league (2025 and 2026 regular seasons)

The constant is set so that league-average FIP equals league-average ERA, so it differs by league and by year. FanGraphs notes that it is generally around 3.10. The values below come from each league's official team pitching totals, run through the FanGraphs formula.

The MLB constants published in the FanGraphs Guts table are 3.100 for 2026 and 3.135 for 2025, which is 0.007 higher than the value calculated from MLB's official totals in both years. If you want the result to match the FIP on a FanGraphs player page, type 3.100 into the constant box. A constant that differs by 0.007 can move the second decimal of a FIP by 0.01.

Because constants differ by league, the same line gives a different FIP depending on which one you use. deGrom's 2026 line is 3.11 with the MLB constant, 3.57 with the KBO constant and 2.79 with the NPB constant. To compare pitchers from different leagues, do not set the FIP numbers side by side. Compare how far each is from its own league average instead. The calculator's "FIP with the league average as 100" row gives that ratio, and deGrom's is 75.

Reading the gap between ERA and FIP

When ERA − FIP is positive, the pitcher allowed more runs than his strikeouts, walks and home runs suggest. When it is negative, he allowed fewer. The MLB glossary says that a pitcher who surrendered a high average on balls in play will likely have a FIP lower than his ERA. FanGraphs says people usually put the difference down to luck on balls in play, and adds that pitchers who can limit the running game or generate fly balls at the expense of line drives or ground balls are more likely to beat their FIP. Over one season the two numbers can move far apart, but in the long run the majority of pitchers end up with an ERA and a FIP that are very close.

Among the 46 qualified MLB pitchers, 18 had an ERA above their FIP and 28 had an ERA below it. In KBO the split was 7 and 11 among 18 pitchers, and in NPB it was 6 and 16 among 22. In all three leagues, more qualified pitchers had an ERA below their FIP than above it. The widest gap in NPB belongs to Yudai Ohno of Chunichi, whose ERA of 2.45 sits 1.55 below his FIP of 4.00. In MLB, deGrom goes the opposite way, with an ERA of 4.20 and a FIP of 3.11.

One home run is worth 6.5 strikeouts

With weights of 13 : 3 : 2, it takes 6.5 strikeouts to cancel one home run, or 4.33 walks and hit batters. One walk is worth 1.5 strikeouts. Because the total is divided by innings, any single event moves FIP more the fewer innings a pitcher has thrown.

A reliever throwing about 60 innings sees one home run lift his FIP by 0.22. That is why FIP over a short stretch swings so much.

What is a good FIP

FIP is built to look exactly like ERA, so you read it the way you read ERA. FanGraphs publishes the rough scale below and warns that it is only an estimate, because league-average FIP is reset every year to equal league-average ERA.

The 2026 league averages are 4.17 in MLB, 4.66 in KBO and 3.31 in NPB, so using this table without regard to league can mislead. A FIP of 4.20 is 0.03 above the MLB average, 0.46 below the KBO average and 0.89 above the NPB average. That is why the calculator shows the 2026 average and the rank among qualified pitchers of the league you pick first, and keeps the rough scale as a reference line.

Common mistakes

• Dividing by 6.1 instead of 6⅓: a line of 6.1 innings has 19 outs. With 1 home run, 2 walks and 7 strikeouts the top of the fraction is 13 + 6 − 14 = 5. Using 5 ÷ 6.1 gives 0.8197, while 5 × 3 ÷ 19 gives 0.7895. Add the MLB constant and you get 3.91 instead of the correct 3.88.
• Leaving out hit batters: the 3 × part takes walks and hit batters together. Dropping deGrom's 2 hit batters makes his FIP 3.07, which is 0.04 too low.
• Taking intentional walks out of the walks: the formula as FanGraphs and MLB write it uses walks (BB) and hit batters (HBP), with no separate term for intentional walks. If you use a formula that removes them, work out the constant the same way, or the league-average FIP will no longer match league-average ERA.
• Using the constant from another league or season: the KBO constant is 0.460 higher than the MLB one, and the MLB constant is 0.313 higher than the NPB one. A 2025 line needs the 2025 constant.
• Mixing up FIP and FIP−: the FIP− from FanGraphs is adjusted for park and league. The calculator's "FIP with the league average as 100" has no park adjustment, so it is not the same number as FIP−.
• Judging a pitcher on one game: FanGraphs says FIP is less effective at describing a single game and is more appropriate over a season's worth of innings.

Limits

• FIP assumes league-average results on balls in play. It leaves out skills that really do prevent runs, such as holding runners or inducing weak contact that turns into outs.
• It is not adjusted for league or park. FanGraphs notes that pitchers in good pitcher's parks will have consistently lower FIPs, as will pitchers in lower-scoring eras. Compare pitchers from the same league and the same year.
• FIP is more of a starting place than a verdict. FanGraphs advises looking into the components of the statistic and other measures of pitcher performance as well.
• The FIP that FanGraphs uses for pitcher WAR is ifFIP, which counts infield fly balls as strikeouts and uses its own constant, so it differs slightly from the FIP on player pages and from this calculator.
• The KBO and NPB constants are calculated from official totals by this calculator. Other record sites may use different formulas or rounding, so their constants can differ slightly.
• League averages and the lists of qualified pitchers are the official regular-season records after the 2026 season ended. Postseason games are not included.

As of The formula and the explanations were checked on 2026-10-23 against the FanGraphs Library and the MLB glossary. Constants, league averages and qualified pitchers were calculated from the KBO record site, the MLB Stats API and the official NPB records: 2026 regular season (fetched 2026-10-21) and 2025 regular season (fetched 2026-10-23).

Sources

• 01FanGraphs Library, FIPPiper Slowinski (2010-02-15): formula and constant formula, weights based on run prevention, defense, luck and sequencing removed, ERA versus FIP, limits for one game, FIP−, rough scale (2016 run environment)
• 02MLB Glossary, Fielding Independent Pitching (FIP)Definition, formula ((HR x 13) + 3 x (BB + HBP) - 2 x K) / IP + FIP constant, a high average on balls in play means FIP is likely lower than ERA
• 03FanGraphs, Guts! (cFIP)MLB FIP constant: 3.100 for 2026, 3.135 for 2025
• 04KBO record site, team pitching2026 regular season, 10 teams: 12,760⅔ innings, 1,366 home runs, 5,319 walks, 838 hit batters, 11,054 strikeouts, 6,606 earned runs. 2025: 12,773⅔ innings, 1,191, 5,123, 806, 11,024, 6,115
• 05KBO record site, player pitching2026 regular season, the 18 qualified pitchers
• 06MLB Stats API, 2026 team pitching30 teams: 43,079⅔ innings, 5,575 home runs, 16,337 walks, 2,118 hit batters, 40,700 strikeouts, 19,966 earned runs. 2025 uses season=2025. The 46 qualified pitchers come from the qualified list of the same API
• 07NPB, Central League team pitching 2026With the Pacific League page (tmp_p.html): 12 teams, 15,276 innings, 1,426 home runs, 4,841 walks, 632 hit batters, 13,430 strikeouts, 5,618 earned runs. 2025 comes from the 2025 pages (web archive copy, 2025-12)
• 08NPB, Central League individual pitching 2026, qualifiedWith the Pacific League page (pit_p.html): 22 pitchers
• 09FanGraphs Library, WAR for PitchersPitcher WAR uses ifFIP, which counts infield fly balls as strikeouts, with its own constant

Frequently asked questions

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