Baseball ERA Calculator
Calculate Earned Run Average for pitchers.
Compare ERA to league averages and historical benchmarks.
ERA Result
ERA (Earned Run Average) is the average number of earned runs a pitcher allows per 9 innings. It is the most common measure of pitching effectiveness.
The formula:
ERA = (Earned Runs / Innings Pitched) × 9
What counts as an earned run:
- Runs scored without the help of errors or passed balls
- Runs that would have scored regardless of defensive mistakes
ERA benchmarks (modern MLB):
- Under 2.50: Elite / Cy Young candidate
- 2.50–3.00: Excellent
- 3.00–3.50: Very good / #1-2 starter
- 3.50–4.00: Above average / solid starter
- 4.00–4.50: Average
- 4.50–5.00: Below average
- Above 5.00: Poor
All-time great ERAs (career):
- Ed Walsh: 1.82
- Mariano Rivera: 2.21
- Clayton Kershaw: ~2.48
- Pedro Martinez: 2.93
League average ERA has varied historically from 2.37 (1968) to 4.77 (2000).