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ERA (earned run average) calculator

Earned run average is the classic pitching stat: the earned runs a pitcher allows per nine innings. ERA = (earned runs × 9) ÷ innings pitched. Innings use the .1 = ⅓, .2 = ⅔ notation, so 180.2 means 180 and two-thirds innings.

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Enter Earned runs (ER), Innings pitched (IP, .1=⅓) and the ERA (earned run average) calculator works out ERA, Innings (decimal) straight away. For instance, with Earned runs (ER) = 27 and Innings pitched (IP, .1=⅓) = 180 it returns ERA = 1.35 and Innings (decimal) = 180.00.

How to use it

  1. Enter your values: Earned runs (ER), Innings pitched (IP, .1=⅓).
  2. Read the result instantly: ERA, Innings (decimal).

Frequently asked questions

What does the ERA (earned run average) calculator actually compute?

It takes Earned runs (ER) and Innings pitched (IP, .1=⅓) and derives ERA and Innings (decimal) from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

2 values: Earned runs (ER) and Innings pitched (IP, .1=⅓). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Earned runs (ER) = 27 and Innings pitched (IP, .1=⅓) = 180, the calculator returns ERA = 1.35 and Innings (decimal) = 180.00. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

When would I actually use this?

Running a league or a tournament: how many fixtures a format produces, how the table resolves ties, and what a team still needs to qualify.

What is the most common mistake?

Comparing two figures produced under different rules. A percentage over ten attempts and one over two hundred are not the same claim; the order of tie-breaks, the way a rating is adjusted and what even counts as an attempt are each set by the competition, not by the sport. The number means something next to the rulebook it came from and very little without it.

What is the difference between the ERA (earned run average) calculator and the At-bats per home run (AB/HR) calculator?

This one returns ERA and Innings (decimal); the At-bats per home run (AB/HR) calculator returns At-bats per home run (AB/HR). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Batting average calculator is the closest one after this: Compute a baseball or softball batting average from hits and at-bats.

What else is worth having open alongside it?

FIP (Fielding Independent Pitching) calculator and WAR (Wins Above Replacement) calculator — simplified — they come up in the same task often enough to be worth a second tab.

Where do the figures come from, and how current are they?

Fixture counts and point totals are pure combinatorics and hold for any competition. The tie-break order is set by each governing body's own regulations — check the one you are actually in.

Further reading

All guides →
ComparisonERA, FIP and WHIP: Three Answers to One QuestionERA measures what happened, FIP measures only what the pitcher controls without his fielders, WHIP measures traffic allowed. Two pitchers can swap places entirely between them — and the gap between ERA and FIP is a forecast, not a verdict.ExplainerHow a Golf Handicap Is Actually Calculated Under the World Handicap SystemBest 8 of your last 20 score differentials, averaged, and no 0.96 multiplier — that disappeared in 2020. Here is the full chain from a gross 92 to a Course Handicap of 17, with the numbers worked out.ExplainerOPS Is a Flawed Sum, and Still the Most Useful Number on the CardOPS adds two fractions with different denominators, which as arithmetic is indefensible. It survives because it tracks run scoring far better than batting average and costs nothing to compute — but it underpays on-base ability, and OPS+ does not fix that.How-toHow to Calculate Batting Average and What .300 MeansBatting average is hits divided by at-bats. Learn how to calculate it, why a .300 hitter is excellent and what counts as an at-bat in baseball.GuideThe Cooper Test: Distance Standards by Age and What They MeanRun as far as you can in twelve minutes, then read the distance against your age and sex. The same number also converts straight into an estimated VO2 max — here is the table and the formula.ExplainerUsage Rate Is Zero-Sum: Five Players Always Add to a Hundred18 shots, 8 free throws and 3 turnovers in 36 minutes gives 29.3 % usage. Five players sharing a team's whole box score get exactly 20 % each — the number is a share, not a skill.