1. What is ERA Percentage?

ERA Percentage (ERA%) is a baseball statistic that compares a pitcher's Earned Run Average to the league average. It shows how much better or worse a pitcher is compared to the league average.

2. How Does the Calculator Work?

The calculator uses the ERA% formula:

Where:

• \( ERA \) — Pitcher's Earned Run Average
• \( League\ Average\ ERA \) — The average ERA across the league

Explanation: An ERA% of 100 means the pitcher is exactly league average. Below 100 is better than average, above 100 is worse than average.

3. Importance of ERA%

Details: ERA% provides context to a pitcher's performance by adjusting for the run environment of the league. It's particularly useful when comparing pitchers across different seasons or leagues with different average ERAs.

4. Using the Calculator

Tips: Enter the pitcher's ERA and the current league average ERA. Both values must be positive numbers. The calculator will show the pitcher's performance relative to league average.

5. Frequently Asked Questions (FAQ)

Q1: What is a good ERA%?
A: Generally, below 85 is excellent, 85-95 is good, 95-105 is average, 105-115 is below average, and above 115 is poor.

Q2: How does ERA% differ from ERA+?
A: ERA+ is similar but scaled differently (100 is average, higher is better). ERA+ = 100 * (League ERA / Pitcher ERA), so it's essentially the inverse of ERA%.

Q3: When is ERA% most useful?
A: When comparing pitchers from different eras or leagues where the average run scoring environment differs significantly.

Q4: What league average ERA should I use?
A: Use the average for the specific league and season you're evaluating. League averages change over time.

Q5: Can ERA% be used for relievers and starters?
A: Yes, but be aware that relievers typically have better ERAs than starters, so their ERA% will naturally be better.