ERA Calculator

ERA (Earned Run Average) measures how many earned runs a pitcher allows per 9 innings. Formula: ERA = (Earned Runs × 9) ÷ Innings Pitched. Example: 20 earned runs in 90 innings = (20 × 9) ÷ 90 = 2.00 ERA. Earned runs exclude runs scored due to fielding errors—only runs the pitcher is responsible for count.

ERA benchmarks vary by era and league, but generally: Below 2.50 = Elite (Cy Young contender). 2.50-3.25 = Excellent (All-Star caliber). 3.25-4.00 = Good (solid starter). 4.00-5.00 = Average (back-end rotation). Above 5.00 = Below average. In high-scoring environments, add 0.50-1.00 to these thresholds. Relief pitchers typically have lower ERAs than starters.

WHIP (Walks plus Hits per Inning Pitched) measures baserunners allowed: WHIP = (Walks + Hits) ÷ Innings Pitched. A 1.00 WHIP means one baserunner per inning. Below 1.00 = Elite. 1.00-1.20 = Excellent. 1.20-1.40 = Good. Above 1.50 = Poor. WHIP complements ERA by showing how many runners a pitcher allows regardless of whether they score.

A quality start requires the starting pitcher to: pitch at least 6 complete innings AND allow 3 or fewer earned runs. This gives a maximum ERA of 4.50 for that game. The stat measures consistency—a pitcher with many quality starts reliably keeps his team in games. About 50% of MLB starts qualify as quality starts.

K/9 (strikeouts per 9 innings) and BB/9 (walks per 9 innings) measure a pitcher's strikeout and walk rates. K/9 = (Strikeouts × 9) ÷ IP. BB/9 = (Walks × 9) ÷ IP. Elite K/9: above 10. Good BB/9: below 2.5. The K/BB ratio (strikeouts divided by walks) is also valuable—elite pitchers have K/BB above 4.0, showing they strike out many more than they walk.