GlossaryBaseball (MLB)
Earned run average (ERA)
ERA is the average number of earned runs a pitcher allows per nine innings — lower is better, and anything under 3.00 is excellent.
ERA = (earned runs ÷ innings pitched) × 9. It excludes runs that scored because of fielding errors ('unearned'), so it isolates the pitcher's own performance. It's the headline pitching stat the way a batting average is for hitters.
Worked example: 20 earned runs over 60 innings pitched is an ERA of 3.00 (20 ÷ 60 × 9).
See it in the numbers
Open the spreadsheet and watch this appear in live scores and standings — disguised as work.
Related terms
How to read a baseball line score
A baseball line score shows runs by inning for each team, then three totals: R (runs), H (hits) and E (errors).
What is a magic number?
A magic number is the combined total of team wins and rival losses needed to clinch a division or playoff spot — when it hits zero, the team is in.
How to read a league table
A league table ranks teams by points; the columns to its right show how those points were earned — games played, wins, draws, losses, goals for and against, and goal difference.
How points work (3-1-0)
In most football leagues a win is worth 3 points, a draw 1 and a loss 0; the team with the most points at the end of the season wins the title.