Earned Run Average Calculator
Earned run average calculator works out Earned run average and Innings pitched (decimal) from Earned runs allowed, Innings pitched and Innings are written as. The default figures on this page give earned run average of 3.00; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- Innings pitched: 9 in box-score thirds is 9 innings (27 outs).
- ERA = 9 x 3 / 9 = 3, quoted as 3.00.
- No hit or walk totals given, so WHIP is zero.
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
2 sources
What the earned run average calculator calculates
Earned run average under Official Baseball Rule 9.17: ERA = 9 x earned runs / innings pitched, with innings entered in box-score thirds (5.2 means five and two-thirds innings) or as a decimal. It also reports WHIP, hits and walks per nine innings, and strikeouts per nine when those totals are supplied.
How to use this earned run average calculator
Enter Earned runs allowed, Innings pitched, Innings are written as and Hits allowed (optional). Earned run average updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Earned run average, Innings pitched (decimal) and Outs recorded.
The method follows Official Baseball Rules, Rule 9.17 (Earned Run Average) and Rule 9.16 (Earned Runs) and MLB official statistics glossary: ERA, WHIP and the recording of innings pitched.
Three earned runs in a complete game example
With Earned runs allowed: 3, Innings pitched: 9, the calculator returns Earned run average: 3, Innings pitched (decimal): 9, Outs recorded: 27. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Earned run average, Innings pitched (decimal) and Outs recorded. The inputs you can vary are Earned runs allowed, Innings pitched, Innings are written as, Hits allowed (optional), Walks allowed (optional) and Strikeouts (optional).
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do you calculate earned run average?
Earned run average under Official Baseball Rule 9.17: ERA = 9 x earned runs / innings pitched, with innings entered in box-score thirds (5.2 means five and two-thirds innings) or as a decimal. Open “How this is worked out” beside the result to see each step for your own figures.
What's considered a good earned run average?
On the figures this page opens with — earned runs allowed 3 and innings pitched 9 — the earned run average is 3. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
Is a 7.00 ERA good?
Earned run average under Official Baseball Rule 9.17: ERA = 9 x earned runs / innings pitched, with innings entered in box-score thirds (5.2 means five and two-thirds innings) or as a decimal. On the figures this page opens with — earned runs allowed 3 and innings pitched 9 — the earned run average is 3. Put your own figures in their place and the working updates beside the result.
How do I calculate my ERA?
It needs Earned runs allowed, Innings pitched, Innings are written as, Hits allowed (optional), Walks allowed (optional) and Strikeouts (optional). Nothing else is required, and the figures stay in your browser.
What information do I need for the earned run average calculator?
You need Earned runs allowed, Innings pitched, Innings are written as, Hits allowed (optional), Walks allowed (optional) and Strikeouts (optional). The page opens with default figures that give earned run average of 3.00, so you can see the scale before entering your own.
What does this earned run average calculator show?
It shows Earned run average, Innings pitched (decimal), Outs recorded, WHIP (walks and hits per inning), Hits per nine innings, Walks per nine innings, Strikeouts per nine innings and Summary, with the working and any warnings for your entries.