Earned Run Average Calculator

Calculate a pitcher's ERA in baseball

About Earned Run Average

Earned Run Average (ERA) is one of the most important statistics for evaluating pitcher performance in baseball. It represents the average number of earned runs a pitcher allows per 9 innings pitched.

ERA Formula:

ERA = (Earned Runs × 9) ÷ Innings Pitched

ERA Classifications:

Excellent (0.00-2.50)

Elite level pitching, Cy Young candidate

Very Good (2.51-3.50)

Above average pitcher, potential All-Star

Average (3.51-4.50)

League average performance

Below Average (4.51-5.50)

Below league average

Poor (5.51+)

Significantly below average

Key Points:

  • Earned Runs Only: ERA excludes runs due to errors
  • 9-Inning Standard: Always calculated per 9 innings
  • Lower is Better: Lower ERA indicates better pitching
  • Context Matters: ERA varies by league, era, and ballpark

Factors Affecting ERA:

  • Defense: Better defense reduces earned runs
  • Ballpark: Some stadiums favor hitters or pitchers
  • League: Different leagues have different offensive levels
  • Era: Offensive levels vary by time period