⚾ How to Calculate Earned Run Average (ERA)

✅ Introduction

Earned Run Average (ERA) is a fundamental baseball statistic used to measure a pitcher’s effectiveness. It tells you the average number of earned runs a pitcher allows per 9 innings pitched.

A lower ERA means the pitcher is performing better at preventing runs.

📌 What Is an Earned Run?

An Earned Run is any run that scores without the help of a fielding error or passed ball.

🧮 ERA Formula (Plain Text)

ERA =

(Earned Runs Allowed × 9) ÷ Innings Pitched

🧪 Example

Let’s say:

• A pitcher gives up 20 earned runs
• Over 50 innings pitched

ERA = (20 × 9) ÷ 50 = 180 ÷ 50 = 3.60

✅ So, the pitcher’s ERA is 3.60

👤 Who Should Use This?

• 🧢 Coaches and scouts
• 📊 Baseball and softball statisticians
• 🧑‍💻 Fantasy baseball players
• ⚾ Sports journalists
• 🎓 Students of sports analytics

🎯 Use Cases

• 📈 Evaluating pitcher performance
• 🏆 Comparing starting pitchers vs relievers
• 📝 Fantasy baseball draft strategy
• 📋 Player scouting and selection
• ⚖️ Deciding bullpen roles

🔍 Key Notes

• ERA is normalized to a 9-inning game
• Lower ERA is better:
  • Under 2.00 = Elite
  • 2.00 – 3.00 = Very good
  • 3.00 – 4.50 = Average
  • Above 5.00 = Needs improvement

❓ FAQs

1. Does ERA include unearned runs?

❌ No. It includes only earned runs (excluding errors and passed balls).

2. How are partial innings handled?

Each out = 1/3 of an inning
e.g., 7 innings and 2 outs = 7.2 innings = 7⅔ innings = 7.666...

3. What’s the difference between ERA and WHIP?

• ERA = Runs allowed per 9 innings
• WHIP = Walks + Hits per inning pitched (measures base runners)

4. Is ERA different for starters vs relievers?

Yes. Starters usually pitch more innings, so their ERA reflects longer performance. Relievers may have fluctuating ERA due to fewer innings.

🛑 Disclaimer

ERA is a traditional stat and doesn’t account for fielding quality or ballpark effects. For deeper insights, use advanced metrics like FIP (Fielding Independent Pitching) or xERA.

📘 Summary

To calculate Earned Run Average (ERA):

👉 ERA = (Earned Runs × 9) ÷ Innings Pitched

This stat gives a fair measure of a pitcher’s run prevention ability, and is a cornerstone in baseball analytics.