Earned Run Average (ERA) Calculator
Earned Run Average is the gold standard for evaluating a pitcher's effectiveness. It tells you how many earned runs a pitcher allows per nine innings. Enter the earned runs and innings pitched to get the ERA instantly.
The ERA formula is simple: ERA = (Earned Runs / Innings Pitched) x 9. Only earned runs count. Runs that score due to errors, passed balls, or other defensive mistakes are unearned and excluded from the calculation.
Understanding innings pitched notation: In baseball, partial innings are written in thirds. A pitcher who records one out in the 7th inning has pitched 6.1 innings (six full innings plus one-third). Two outs would be 6.2 innings (six and two-thirds). This calculator automatically handles that notation.
Historical context for ERA benchmarks:
- Below 2.00: Historically rare. Bob Gibson's 1.12 ERA in 1968 is one of the modern-era records.
- 2.00-3.00: Excellent. Consistently found among Cy Young contenders.
- 3.00-4.00: Good to very good for starting pitchers.
- 4.00-4.50: League average, which has fluctuated between 3.80 and 4.50 over different eras.
- Above 5.00: Generally considered poor for a starting pitcher.
Keep in mind that ERA does not tell the whole story. Factors like ballpark, league (NL vs AL before universal DH), defense quality, and luck on balls in play all influence ERA. Advanced metrics like FIP (Fielding Independent Pitching) attempt to isolate what the pitcher controls.