An easy tool for calculating earned run average in baseball with grading scale for evaluation.
ERA Calculator
How to Use This Earned Run Average Calculator
Earned Runs (ER)
To use this ERA calculator, start by entering the total number of earned runs the pitcher has allowed in the first input box. Only include earned runs—do not count runs that resulted from errors or passed balls, as those are unearned and do not factor into ERA.
Full Innings Pitched (IP)
Next, enter the number of full innings pitched in the second input box. A full inning means recording three outs in that inning. For example, if a pitcher completes six innings and leaves the game before getting any additional outs, enter 6 in this box. Do not enter any partial innings in this field—those will be handled separately.
Partial Innings (If Needed)
Now, if the total number of innings pitched has a partial inning (for example, 45.1 IP), use the Partial Innings (If Needed) dropdown menu to account for those partial innings.
- Select .1 for 1/3 of an inning.
- Select .2 for 2/3 of an inning.
- Select None if the pitcher only pitched full innings with no partials.
For example, if a pitcher has thrown 45.1 total innings, enter 45 in the Full Innings Pitched field and select .1 (1/3 inning) from the dropdown.
What Not to Do
- Do not include unearned runs in the Earned Runs (ER) field.
- Do not enter partial innings as decimals in the Full Innings Pitched field. Use the dropdown instead.
- Do not enter a negative number or leave any required fields blank, as this will result in an error.
Once all values are entered into the Earned Run Average calculator, click Calculate ERA to get the result. The ERA will be displayed along with a grade to help evaluate performance.
Using our online pitch counter tool to track total pitches.
ERA Formula
The Earned Run Average calculator above makes it easy for you to calculate ERA for 9 innings. However, if you want to do it on your own, you can use the ERA formula to calculate Earned Run Average. This is the formula for ERA:
ERA = (Earned Runs Ă· Innings Pitched) Ă— 9
For example, if a pitcher gives up 20 earned runs in 50 innings, their ERA is (20 Ă· 50) Ă— 9 = 3.60. This means they allow an average of 3.60 runs every nine innings.
How to Use an ERA Formula
As we discussed earlier, you need to understand what type of runs count when calculating ERA. Remember, only earned runs count. Earned run are runs that result from hits, walks, or other legal plays.
Errors and passed balls do not count as earned runs. Innings pitched include both full innings and partial innings. For example, 6.2 innings means six full innings plus two-thirds of an inning.
So if someone pitched 5 full innings then got 1 out in the 6th inning, that would constitute 5.1 innings pitched.
What is Earned Run Average?
Earned Run Average (ERA) tells how many earned runs a pitcher allows per nine innings. It’s a key stat for evaluating pitchers. A lower ERA means better pitching performance because it shows the pitcher is keeping runs off the scoreboard.
What’s a Good ERA
If you are using the ERA calculator and want to know how the ERA might compare, these general guidelines might help categorize pitchers.
Below 2.00 – Elite (Hall of Fame Level)
2.00 – 3.00 – Great (Top-tier starters and closers)
3.00 – 4.00 – Good (Reliable pitchers)
4.00 – 5.00 – Average (Backend MLB starters)
Above 5.00 – Below Average (Struggling pitchers)
ERA vs. Other Pitching Stats
Using our ERA calculator is a fun way to evaluate stats. And, yes, ERA is important, but it doesn’t tell the full story. Other stats help analyze a pitcher’s effectiveness.
WHIP (Walks + Hits per Inning Pitched)
WHIP shows how many base runners a pitcher allows per inning. A WHIP under 1.10 is excellent, while anything above 1.50 suggests trouble keeping runners off base. WHIP Calculator
FIP (Fielding Independent Pitching)
FIP removes the effects of defense and focuses only on strikeouts, walks, and home runs. A pitcher with a low FIP but high ERA might be unlucky or have poor defensive support.
ERA+ (ERA Adjusted for Ballparks and League Averages)
ERA+ compares a pitcher’s ERA to the league average while adjusting for ballpark effects. A score of 100 is league average, while 120 or higher is elite.
Factors That Affect ERA
Defense Behind the Pitcher
A strong defensive team helps lower ERA by making more outs and turning double plays. A pitcher on a weak defensive team may allow more runs due to errors, even if those runs aren’t counted as earned. This can also affect the pitcher’s batting average against stats.
Ballparks and Weather
Some stadiums favor pitchers, while others help hitters. Smaller ballparks will lead to more runs scored, while larger ballparks will make it harder to generate extra base hits, and can lead to a lower ERA.
Bullpen Support
Starters rely on relievers to keep their ERA in check. If a relief pitcher allows inherited runners to score, those runs count against the starter’s ERA, even though they didn’t give them up.
Why ERA Can Be Misleading
Calculating ERA can be fun, but ERA has flaws that can make a pitcher appear better or worse than they actually are. Since ERA relies on earned runs, it is heavily influenced by external factors like defense, ballparks, and bullpen performance.
Fielding plays a huge role in ERA. A pitcher with a strong defense behind them will have fewer balls drop in for hits, leading to fewer earned runs. On the other hand, a pitcher playing with a poor defensive team may have a higher ERA simply because their fielders fail to make plays. ERA does not account for this, making it less reliable as a true measure of a pitcher’s ability.
Stadium effects can also impact ERA. Some parks are known for favoring hitters, while others give pitchers an advantage. A pitcher who plays half their games at a hitter-friendly park may naturally have a higher ERA than one who plays in a large, pitcher-friendly stadium.
Another issue with ERA is that it doesn’t separate a pitcher’s performance from their bullpen’s. If a starter leaves the game with runners on base and a reliever allows those runners to score, those runs still count against the starter’s ERA. This can make a good pitcher look worse simply because of poor bullpen support.
To adjust for these flaws, advanced pitching stats like Fielding Independent Pitching (FIP) and Expected ERA (xERA) attempt to isolate a pitcher’s individual performance. FIP focuses on strikeouts, walks, and home runs allowed, removing the impact of defense and ballpark factors. xERA takes expected outcomes based on batted ball data to show what a pitcher’s ERA should be, rather than what it actually is.
Using our Earned Run Average calculator will help give you a general idea on performance. Just remember, these other advanced stats help provide a clearer picture of a pitcher’s true skill level beyond what traditional ERA can show.