ERA Calculator (Earned Run Average)
Calculate a pitcher's earned run average from earned runs and innings pitched.
How to use the era calculator
- Enter earned runs allowed and innings pitched.
- Set innings per game (9 for baseball, 7 for softball).
- Click Calculate for the ERA.
Earned versus unearned runs
ERA counts only earned runs — those not caused by fielding errors — so it isolates the pitcher's own performance from defensive mistakes behind them.
Frequently asked questions
How is ERA calculated?
ERA = (earned runs × innings per game) ÷ innings pitched. It expresses how many earned runs a pitcher allows per full game.
What is a good ERA?
Under 3.00 is excellent for a starter, around 4.00 is average, and above 5.00 is poor in Major League Baseball.
Related tools
Batting Average Calculator
Calculate a baseball or softball batting average from hits and at-bats.
Slugging Percentage Calculator
Measure hitting power by calculating slugging percentage from total bases and at-bats.
Winning Percentage Calculator
Calculate a team or player's winning percentage from a win-loss-tie record.