ERA and WHIP.

Worked example

A start of 6.1 innings (6 and one third) with 2 earned runs, 5 hits and 2 walks. Innings = 6.333. ERA = 9 × 2 / 6.333 = 2.84. WHIP = (2 + 5) / 6.333 = 1.11. The same line over 7-inning games gives an ERA of 7 × 2 / 6.333 = 2.21.

How it works

ERA = 9 × earned runs / innings pitched. WHIP = (walks + hits) / innings pitched. Only earned runs count, meaning runs that scored without the aid of an error or a passed ball.

Box scores write partial innings as .1 and .2, which are thirds, not tenths: 6.1 is 6.333 innings and 6.2 is 6.667. Typing 6.3 is not valid. Softball and some youth leagues measure ERA over 7 innings, so the same formula uses 7 in place of 9; check your league’s rule.

Sources and basis (checked 2026-10-05): MLB.com Glossary, Earned Run Average (9 x earned runs / innings pitched); MLB.com Glossary, Walks and Hits per Inning Pitched.

FAQ

How do you calculate ERA?

Multiply earned runs by 9 and divide by innings pitched. 2 earned runs in 6.1 innings is 9 x 2 / 6.333 = 2.84.

How do I enter 6 and 2/3 innings?

Type 6.2. The digit after the point is outs, so .1 is one third and .2 is two thirds of an inning.

What is WHIP?

Walks plus hits per inning pitched. Add walks and hits, then divide by innings pitched.

Do unearned runs count in ERA?

No. Only earned runs count, which are runs scored without the help of an error or passed ball.

What ERA formula does softball use?

The formula is the same with the number of innings in a regulation game. Many softball leagues use 7, so ERA = 7 x earned runs / innings pitched.