ERA Calculator
Find a pitcher's earned run average in seconds. Type innings the way they appear in a box score (5.2 means 5⅔ innings), choose a 9 or 7 inning game, and see ERA, WHIP, strikeout rate and how many scoreless innings it takes to reach a goal.
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Box-score style: 62.1 = 62 innings + 1 out, 62.2 = 62 + 2 outs.
With walks, gives WHIP.
Gives K per game and K/BB.
How many scoreless innings to get there.
How to use the ERA Calculator
- Enter the earned runs charged to the pitcher (not unearned runs).
- Enter innings pitched in box-score form: 6.1 is 6⅓ innings and 6.2 is 6⅔. Pick True decimal if your number is already 6.333.
- Choose the game length: 9 innings for MLB and college, 7 for high school baseball and softball.
- Optionally add hits, walks and strikeouts for WHIP and strikeout rates, and a target ERA.
- Press Calculate ERA to see the result, the working, and how the ERA would change over the next innings.
ERA formula
- ERA = earned runs × innings per game ÷ innings pitched
- Innings pitched = outs recorded ÷ 3 (box score 7.2 = 23 outs = 7.667 innings)
- WHIP = (walks + hits) ÷ innings pitched
- K/9 = strikeouts × 9 ÷ innings pitched
Example: a starter allows 3 earned runs in 5.2 innings. 5.2 is 5 innings and 2 outs, or 17 outs, which is 5.667 innings. ERA = 3 × 9 ÷ 5.667 = 4.76. The most common mistake is typing 5.2 straight into the formula, which gives 5.19 instead.
Box-score innings to decimal
| Box score | Innings as a fraction | Decimal innings | Outs |
|---|---|---|---|
| 0.1 | ⅓ | 0.333 | 1 |
| 0.2 | ⅔ | 0.667 | 2 |
| 1.0 | 1 | 1.000 | 3 |
| 5.1 | 5⅓ | 5.333 | 16 |
| 6.2 | 6⅔ | 6.667 | 20 |
| 7.0 | 7 | 7.000 | 21 |
| 200.1 | 200⅓ | 200.333 | 601 |
Rough ERA guide (9-inning scale)
| ERA | What it usually means at the pro level |
|---|---|
| Under 2.00 | Elite, award-level season |
| 2.00 – 2.99 | Excellent |
| 3.00 – 3.74 | Above average |
| 3.75 – 4.49 | About league average |
| 4.50 – 5.49 | Below average |
| 5.50 and up | Poor |
Small samples swing wildly: one bad inning can push a reliever's early-season ERA above 10. Look at innings pitched alongside ERA, and compare pitchers within the same league and season, since run-scoring environments change over time.
Frequently asked questions
How do you calculate ERA?
Multiply earned runs by 9 and divide by innings pitched. A pitcher who allows 18 earned runs in 62⅓ innings has an ERA of 18 × 9 ÷ 62.333 = 2.60. For 7-inning games (high school baseball, softball) multiply by 7 instead of 9.
What does 6.2 innings pitched mean?
Innings are recorded in thirds because each inning has three outs. In a box score 6.1 means 6 innings plus 1 out (6⅓) and 6.2 means 6 innings plus 2 outs (6⅔). You should never see .3; three outs make a full inning. Convert to outs (6.2 = 20 outs) and divide by 3 before using the ERA formula.
What is a good ERA?
In modern Major League Baseball an ERA under 3.00 is excellent, around 4.00 to 4.50 is roughly league average, and above 5.00 is below average. Youth, high school and amateur leagues often run higher because of more errors and walks, so compare a pitcher with others at the same level.
What is the difference between earned and unearned runs?
An earned run is one the pitcher is responsible for. Runs that score because of an error or a passed ball, and that would not have scored otherwise, are unearned and are left out of ERA. The official scorer decides which runs are earned.
How is softball ERA calculated?
Softball games are 7 innings, so softball ERA = earned runs × 7 ÷ innings pitched. Choose the 7-inning option and the calculator uses 7 while also showing the 9-inning equivalent.
What is WHIP?
WHIP is walks plus hits per inning pitched: (walks + hits) ÷ innings. It measures how many base runners a pitcher allows. Around 1.00 is outstanding and about 1.30 is typical in the major leagues.
How many scoreless innings will lower my ERA to a target?
Divide earned runs × 9 by the target ERA to get the total innings needed, then subtract the innings already pitched. With 18 earned runs a 2.25 ERA needs 18 × 9 ÷ 2.25 = 72 innings, so a pitcher at 62⅓ needs 9⅔ more scoreless innings.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.