Skip to content
Omnikalc

ERA calculator: earned run average, WHIP and strikeout rate

Calculate a pitcher's earned run average, WHIP, strikeouts and walks per nine innings, and strikeout-to-walk ratio.

Updated on
Your inputs

Value out of range

Plus outs

Value out of range

Value out of range

Value out of range

Value out of range

Innings per game

Results

Earned run average (ERA)

3.00

Good

WHIP (walks + hits per inning)

1.17

Strikeouts per 9 innings (K/9)
9.5
Walks per 9 innings (BB/9)
2.5
Strikeout-to-walk ratio (K/BB)
3.80

The main pitching statistics

  • ERA (earned run average) = 9 × earned runs ÷ innings pitched
  • WHIP = (walks + hits) ÷ innings pitched
  • K/9 = 9 × strikeouts ÷ innings pitched
  • BB/9 = 9 × walks ÷ innings pitched
  • K/BB = strikeouts ÷ walks

For leagues that play 7-inning games, such as high school baseball and softball, ERA uses 7 instead of 9.

Innings pitched notation

Box scores write partial innings with a decimal that counts outs, not tenths: 6.1 means 6⅓ innings and 6.2 means 6⅔ innings. This calculator asks for full innings and outs separately to avoid that trap.

Worked example

A starter throws 180 innings, allowing 60 earned runs, 160 hits and 50 walks, with 190 strikeouts.

  1. ERA: 9 × 60 ÷ 180 = 3.00.
  2. WHIP: (50 + 160) ÷ 180 = 1.17.
  3. K/9: 9 × 190 ÷ 180 = 9.5.
  4. BB/9: 9 × 50 ÷ 180 = 2.5.
  5. K/BB: 190 ÷ 50 = 3.80.

Benchmarks

Stat Excellent Good Around MLB average
ERA under 3.00 3.00 to 3.75 about 4.00 to 4.30
WHIP under 1.10 1.10 to 1.25 about 1.30
K/9 over 10 9 about 8.5
BB/9 under 2.5 3 about 3.2
K/BB over 4 3 about 2.6

Earned and unearned runs

A run is unearned if it would not have scored without a fielding error or a passed ball. The official scorer reconstructs the inning without the error to decide. Unearned runs are left out of ERA so that the stat reflects the pitcher, not the defense.

Limits of ERA

ERA still depends on the defense behind the pitcher, the ballpark and luck on balls in play. Analysts often use FIP (fielding independent pitching), which only uses strikeouts, walks, hit batters and home runs, to judge pitchers over shorter periods.

Qualifying for the ERA title

In MLB, a pitcher needs at least 1 inning pitched per team game, 162 innings in a full season, to qualify for league leaderboards.

Frequently asked questions

How do you calculate ERA?

ERA = 9 × earned runs ÷ innings pitched. A pitcher allowing 60 earned runs in 180 innings has a 3.00 ERA. For 7-inning games, such as high school or softball, use 7 instead of 9.

How do I enter partial innings?

Box scores write one out as .1 and two outs as .2, so 6.2 innings means 6 2/3 innings. Enter the full innings and the extra outs separately.

What is a good WHIP?

WHIP is walks plus hits per inning. Under 1.00 is elite, around 1.10 to 1.20 very good and about 1.30 near the MLB average in recent seasons.

What is the difference between earned and unearned runs?

Runs that score because of a fielding error or passed ball are unearned and are left out of ERA, so it reflects the pitcher's performance rather than the defense.

Was this calculator helpful?

Thanks for your feedback!

Results are estimates provided for information purposes. They do not replace professional advice.

Related calculators