ERA Calculator
ERA (Earned Run Average) measures a pitcher's effectiveness in baseball. It shows how many earned runs a pitcher allows per 9 innings. Calculating ERA helps compare pitcher performance, evaluate player value, and make strategic decisions in baseball games.
Calculate ERA
ERA Formula
ERA = (Earned Runs × 9) ÷ Innings Pitched
Calculation Process
- Count all earned runs allowed by the pitcher
- Count total innings pitched
- Multiply earned runs by 9
- Divide by innings pitched
- Round to two decimal places
ERA Examples
| Earned Runs | Innings | ERA |
|---|---|---|
| 3 | 9 | 3.00 |
| 5 | 7 | 6.43 |
| 2 | 6 | 3.00 |
FAQs
What counts as an earned run?
Earned runs are runs that score without the aid of errors or passed balls. They result directly from hits, walks, or hit batters. Umpires determine earned runs based on official scoring rules in baseball.
How to calculate ERA for partial innings?
Partial innings are converted to decimal form (e.g., 6.1 innings = 6.33). Each out counts as 0.33 innings. For 6.2 innings, use 6.67 in calculations. This allows accurate ERA computation for any pitching duration.
What's a good ERA in baseball?
An ERA below 4.00 is generally good, while below 3.00 is excellent. The average ERA varies by league and era. Relief pitchers typically have lower ERAs than starters due to shorter outings.
Does ERA include unearned runs?
No, ERA only considers earned runs. Unearned runs resulting from errors don't affect ERA. This distinguishes pitcher performance from team defensive skills in statistical analysis.
How does ballpark affect ERA?
Ballpark dimensions can influence ERA. Pitchers in hitter-friendly parks may have higher ERAs. Advanced metrics like ERA+ adjust for ballpark factors to enable fair comparisons across different stadiums.
Can ERA be negative?
No, ERA cannot be negative. The lowest possible ERA is 0.00. Relief pitchers might have 0.00 ERA if they pitch few innings without allowing runs, but it's rare over full seasons.
How often is ERA calculated?
ERA is calculated after each game and tracked season-long. Career ERA aggregates all performances. Teams update ERA statistics daily during baseball season for accurate player evaluation.
What's the difference between ERA and WHIP?
WHIP measures walks plus hits per inning pitched, while ERA focuses on runs allowed. Both measure pitching effectiveness but assess different aspects of performance (base runners vs. run prevention).
How to improve ERA?
Pitchers can lower ERA by allowing fewer hits/walks, striking out more batters, and inducing ground balls. Defensive improvements and strategic pitching changes also help reduce earned runs.
Who holds the best career ERA?
Ed Walsh holds the MLB record with 1.82 career ERA (1904-1917). Modern leaders typically have ERAs around 2.00-3.00. Career ERA leaders are mostly from early 20th century dead-ball era.