1. What is ERA?

ERA (Earned Run Average) is a statistic in baseball that measures a pitcher's effectiveness, calculated as the average number of earned runs given up by a pitcher per nine innings pitched.

2. How Does the Calculator Work?

The calculator uses the standard ERA formula:

Where:

• Earned Runs — Runs for which the pitcher is held accountable
• Innings Pitched — Number of innings the pitcher has thrown
• 9 — Represents a standard 9-inning baseball game

Explanation: The formula scales the earned runs to a standard 9-inning game to allow comparison between pitchers who have pitched different numbers of innings.

3. Importance of ERA Calculation

Details: ERA is one of the most important statistics for evaluating pitcher performance, as it directly measures how many runs a pitcher allows per game.

4. Using the Calculator

Tips: Enter total earned runs allowed by the pitcher and total innings pitched (can include fractions like 6.2 for 6⅔ innings). Both values must be valid (earned runs ≥ 0, innings pitched > 0).

5. Frequently Asked Questions (FAQ)

Q1: What's considered a good ERA?
A: In modern MLB, ERA below 4.00 is generally good, below 3.00 is excellent, and below 2.00 is exceptional.

Q2: How does ERA differ from WHIP?
A: WHIP measures baserunners allowed per inning, while ERA measures runs allowed per 9 innings. ERA accounts for run-scoring impact.

Q3: Why multiply by 9 in the formula?
A: This standardizes the metric to a full 9-inning game, allowing comparison between starters and relievers.

Q4: Are unearned runs included in ERA?
A: No, only earned runs count toward ERA. Unearned runs result from fielding errors.

Q5: What's the lowest possible ERA?
A: The theoretical minimum is 0.00, achieved by allowing no earned runs.