ERA tells you what happened. FIP tells you what a pitcher actually deserved. If you want to know how good a pitcher really is, FIP is the number you need.
What Is FIP?
FIP stands for Fielding Independent Pitching, and it measures a pitcher's performance based only on the outcomes they directly control: strikeouts, walks, hit by pitches, and home runs. Everything else, like whether a fielder ranges left to snag a grounder or boots an easy pop-up, gets removed from the equation entirely. The formula was developed by sabermetrician Tom Tango and is scaled to look like ERA so the numbers feel familiar.
The math behind it is straightforward. Home runs allowed get weighted heavily because they're automatic runs. Strikeouts are good for the pitcher. Walks and hit batters are bad. A league-wide constant brings the result onto an ERA scale, so a 3.50 FIP reads roughly the same as a 3.50 ERA. You're just measuring something more honest.
You can dig into the formula and league-constant details at FanGraphs Library.
Why Can't Pitchers Control Everything That Happens on Balls in Play?
Once a batter makes contact and the ball lands in the field of play, the pitcher has almost no say in what happens next. Research going back to Voros McCracken's work in the early 2000s showed that pitchers have very little year-to-year control over their batting average on balls in play (BABIP). A liner up the middle is a hit or an out depending on the shortstop's range, the outfielder's jump, and plain luck. The pitcher can't change that in the moment.
This is why a pitcher can have a 4.50 ERA one year and a 3.20 ERA the next without pitching any differently. If his defense improved, if balls started finding gloves instead of gaps, his ERA drops. But his FIP might stay flat, signaling that he's the same pitcher he was before.
ERA punishes pitchers for things that aren't their fault and rewards them for things that have nothing to do with their skill. FIP cuts through all of that.
How Big Is the Gap Between ERA and FIP in Real Examples?
The gaps can be enormous, and they tell a story. Take the 2014 season. Felix Hernandez posted a 2.14 ERA that year, one of the best marks in baseball. His FIP was 2.97. He was excellent either way, but the ERA made him look almost untouchable. A chunk of that gap came from Seattle's defense and a low BABIP working in his favor.
The flip side happens too. A pitcher carries a bloated ERA because his team's defense is leaking runs behind him, but his FIP is sharp. Teams and analysts use this signal to identify undervalued arms, guys who are pitching better than their ERA suggests and will likely see their ERA fall back toward their FIP over time.
This regression toward FIP is one of its most useful predictive properties. ERA fluctuates with luck. FIP stabilizes faster and predicts the next batch of starts more accurately than ERA does.
What Is a Good FIP?
FIP uses the same scale as ERA, so your intuition from ERA carries over. Anything below 3.00 is elite. The range from 3.00 to 3.75 is very good. From 3.75 to 4.50 is average to slightly above. Above 4.50 starts to look rough, and above 5.00 is a problem. League average FIP typically sits in the low-to-mid 4.00s, depending on the run environment of the season.
Context still matters. A 4.20 FIP in a high-offense era looks different than the same number in a pitcher-friendly year. Always compare a pitcher's FIP to the league average for the season you're looking at. FanGraphs does this automatically and even color-codes the numbers so you can scan a leaderboard at a glance.
How Does FIP Compare to xFIP and SIERA?
FIP is the entry point, but it has a limitation. It takes home runs allowed at face value. Some pitchers consistently allow fewer home runs per fly ball than league average. Others consistently give up more. FIP doesn't adjust for that tendency, which can make a fly-ball pitcher look worse than he is, or inflate the numbers of a ground-ball pitcher who happened to give up some cheap homers.
xFIP (expected FIP) fixes this by swapping in a league-average home run per fly ball rate instead of the pitcher's actual rate. It's asking the question: if this pitcher's fly balls turned into home runs at the same rate as everyone else, what would his FIP look like?
SIERA (Skill-Interactive ERA) goes even further, accounting for how different types of batted balls behave differently and how strikeout and walk rates interact. It's the most sophisticated of the three but also the hardest to internalize quickly.
For most conversations, FIP is the right tool. It's simple enough to explain in a sentence, widely available, and already more informative than ERA for evaluating pitcher skill.
Why Do Scouts and Analysts Still Watch ERA?
ERA isn't useless. It's the actual run-prevention record, and at the end of the day, run prevention is what wins games. If a pitcher's ERA stays below his FIP for multiple seasons, it's worth asking whether he has a real skill at suppressing hits on contact, like an extreme ground-ball approach that keeps balls away from outfield gaps, or a deceptive delivery that leads to weak contact.
ERA also matters in context. A pitcher's job is to keep runs off the board, whatever the source. A starter who consistently escapes jams, strands runners, and pitches better with men on base might outperform his FIP year after year. That's a real skill, even if it's hard to isolate.
The honest answer is that analysts use both. ERA tells you outcomes. FIP tells you process. The gap between them tells you something about luck, defense, and sequencing. Understanding all three gives you a much fuller picture than any single number alone.
How Does This Apply to GAGE Predictions?
When you're making predictions on pitcher stats in GAGE, ERA is the number everyone sees. It's the headline. But FIP is the number that tells you what's coming. A pitcher with a 5.00 ERA and a 3.60 FIP is almost certainly about to pitch better than his recent results suggest. A pitcher with a 2.80 ERA and a 4.40 FIP might be due for a rough stretch. These gaps are where smart predictions come from.
GAGE scores predictions against implied probability, not against each other. That means finding inefficiencies in how performance is perceived versus what the underlying numbers say is exactly the kind of edge that matters. FIP is one of the sharpest tools for that job in baseball.
Download GAGE and put your pitcher reads to the test against real lines.
Is FIP better than ERA for evaluating pitchers?
For predicting future performance, yes. FIP isolates what a pitcher controls and ignores luck and defense. It stabilizes faster than ERA and correlates more strongly with how a pitcher performs in future seasons.
Where can I find FIP stats?
FanGraphs tracks FIP, xFIP, and SIERA for every pitcher going back decades. Their leaderboards and player pages are the standard source. Baseball Savant also surfaces related Statcast metrics like expected ERA.
What FIP is considered average for an MLB starter?
League average FIP for starting pitchers typically falls between 4.00 and 4.50, depending on the season. Anything below 3.75 is above average, and below 3.25 is genuinely excellent.