ERA Calculator
Calculate a pitcher's Earned Run Average (ERA) instantly. Enter earned runs and innings pitched for your result.
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About This Tool
What it does
Calculates Earned Run Average (ERA) — the primary pitching statistic in baseball. ERA represents the average number of earned runs a pitcher allows per 9 innings. Handles partial innings correctly and shows a rating against MLB standards.
Who it's for
Baseball coaches, players, fantasy baseball managers and fans tracking pitching performance in MLB, NPB (Japan), KBO (Korea), amateur leagues and youth baseball. Popular in the US, Japan, South Korea, Dominican Republic, Canada and Australia.
Your privacy
All calculations happen in your browser. No data is transmitted or stored anywhere.
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Frequently Asked Questions
How is ERA calculated?
ERA = (Earned Runs ÷ Innings Pitched) × 9. It represents the average earned runs allowed over a complete 9-inning game. Unearned runs (scored due to fielding errors) are excluded.
What is a good ERA?
In MLB: under 3.00 is excellent (ace-level), 3.00-3.99 is above average, 4.00-4.99 is average, 5.00+ is below average. Standards differ between leagues and historical eras — deadball era ERAs were much lower than modern ones.
What is the difference between ERA and WHIP?
ERA measures runs allowed per 9 innings. WHIP (Walks + Hits per Inning Pitched) measures baserunners allowed. ERA is the traditional standard; WHIP is a modern sabermetric measure of run prevention.
How do I enter partial innings?
Partial innings are expressed as thirds: 1 out = .1, 2 outs = .2. A pitcher through 5 innings with 1 out enters 5.1. This calculator converts .1 and .2 to 0.333 and 0.667 automatically.
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