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ERA Calculator

Home runs per nine

HR/9 Calculator

Calculate home runs allowed per nine innings from home runs and innings pitched.

HR/9

HR/9 1.14. 12 home runs over 95 innings.

Outs recorded in the final inning

Baseball notation works too: type 6.1 for 6⅓ or 6.2 for 6⅔ innings.

How this result was calculated

  • HR/9 = 12 × 27 ÷ 285 outs = 1.14
  • (12 × 9 ÷ 95 innings)

Meaning

What is HR/9?

HR/9 is home runs allowed per nine innings. Because home runs almost always score and are weighted heavily in FIP, this rate is one of the clearest signals of a pitcher's power-prevention profile.

Park factors swing HR/9 more than many other rates. Compare pitchers in similar parks and eras before drawing hard conclusions from small samples.

Formula

The formula

HR/9 = (Home Runs Allowed × 9) ÷ Innings Pitched

Same outs form: HR/9 = home runs × 27 ÷ outs. FIP multiplies each home run by 13 before dividing — HR/9 is the simpler per-nine rate.

Partial innings use .1 / .2 baseball notation and are converted to outs.

How to calculate

Step by step

  1. Total home runs allowed.
  2. Convert innings pitched to outs.
  3. Multiply home runs by 27 and divide by outs.
  4. Round to two decimal places.

Worked example

12 home runs in 90.0 innings is 12 × 9 ÷ 90 = 1.20 HR/9.

Related

HR/9 and FIP

FIP treats home runs as the costliest event in its formula. A rising HR/9 usually lifts FIP quickly even if walk and strikeout rates stay flat. Pair HR/9 with FIP and ERA to see whether the long ball is the main story.

HR/9 is especially relevant when calculating FIP Calculator.

Home runs also drive earned runs — check the ERA Calculator.

FAQ

Common questions

How do you calculate HR/9?

Multiply home runs allowed by 9 and divide by innings pitched, or use home runs × 27 ÷ outs.

What is a good HR/9?

In recent MLB seasons, roughly 1.0–1.2 is solid and under 1.0 is excellent for a starter. Coors Field and similar parks inflate the number — adjust expectations for venue.

Do inside-the-park home runs count?

Yes if they are scored as home runs. Enter the official home-run total from the pitching line.

Why does HR/9 matter for FIP?

The FIP formula weights each home run by 13 — far more than a walk — so home-run rate is one of the biggest levers on Fielding Independent Pitching.

Related

Related pitching calculators

Connect HR/9 to FIP, ERA and the other rate stats that fill out a pitching profile.

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