ERA Calculator
Calculate a pitcher’s earned run average from earned runs allowed and innings pitched, including partial innings, for 9-inning or shorter games.
ERA formula
ERA = 9 × earned runs ÷ innings pitched
Earned run average shows how many earned runs a pitcher allows per nine innings. For leagues that play 7-inning games, such as many high school and softball leagues, use 7 instead of 9.
Worked example
A pitcher who allows 30 earned runs in 120 innings has an ERA of 9 × 30 ÷ 120 = 2.25.
Partial innings
Innings are recorded in thirds, one for each out. 6.1 means 6⅓ innings and 6.2 means 6⅔. The calculator converts these automatically.
Frequently asked questions
What is a good ERA?
In professional baseball, an ERA under 3.00 is excellent and around 4.00 is roughly average, depending on the era and league.
What is an earned run?
A run that scores without the help of a fielding error or passed ball.
Why is 6.1 innings not 6.1 in the formula?
Because .1 means one out, a third of an inning, so 6.1 innings is 6.333.
How do I calculate ERA for softball?
Use 7 innings per game instead of 9.
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