ERA Calculator — Earned Run Average
Calculate a pitcher's ERA by entering earned runs allowed and innings pitched (with optional partial-inning outs). The result is scaled against MLB ERA benchmarks so you can instantly see whether the ERA is elite, above average, or high.
innings
Earned runs allowed per 9 innings pitched
- 1
Innings pitched (decimal)
100 + 0 ÷ 3 = 100Each additional out equals ⅓ of an inning. - 2
Earned runs per inning
30 ÷ 100 = 0.3 - 3
ERA (× 9 innings)
0.3 × 9 = 2.70
How does this calculator work?
ERA = (Earned Runs ÷ Innings Pitched) × 9. It measures how many earned runs a pitcher gives up per full game (9 innings). A sub-3.50 ERA is above average in MLB; elite starters typically post ERA below 2.50. Partial innings are counted as full-innings equivalents (each out = ⅓ inning).
Formula
How this is calculated
ERA (Earned Run Average) measures how many earned runs a pitcher allows per nine innings — a full regulation game. Only earned runs count: unearned runs that score due to fielding errors or passed balls are excluded, because those are not the pitcher's responsibility. The formula is: ERA = (ER ÷ IP) × 9.
Innings pitched in baseball use a fractional notation: "6.2" in a box score means 6 full innings plus 2 outs, which equals 6⅔ innings (6.667 in decimal). This calculator takes full innings and additional outs separately, converts to decimal, and applies the formula. One "out" corresponds to ⅓ of an inning, so 0, 1, and 2 additional outs add 0, 0.333, or 0.667 to the innings total.
ERA is the standard measure of pitching quality in Major League Baseball. Historical MLB league-average ERA has ranged from around 4.00 to 4.50 in recent seasons (2020–2024). An ERA below 3.00 is considered excellent, and sub-2.50 is elite starter territory. ERA can be misleading in small samples (fewer than 30–40 innings) because a single bad outing skews the stat; more robust modern alternatives include FIP (Fielding-Independent Pitching) and xFIP.
Frequently asked questions
In recent MLB seasons (2020–2024) a league-average ERA is roughly 4.00–4.50. An ERA below 3.50 is considered above average, below 3.00 is excellent, and below 2.50 is elite. Anything above 5.00 indicates a pitcher who is struggling. Context matters: ERA is park-dependent and influenced by the team's defence.
ERA measures how many earned runs a pitcher allows per 9 innings. WHIP (Walks plus Hits per Inning Pitched) measures how many base-runners the pitcher allows per inning. A pitcher can have a low ERA with a high WHIP if they strand runners effectively, but the two stats usually move together. Both ignore unearned runs.
Unearned runs score only because a fielder committed an error or a catcher had a passed ball, extending an inning that should have ended. Because those runs result from defensive failures rather than pitching failures, they are excluded to give a cleaner measure of the pitcher's individual effectiveness.
TG we-Calculate Editorial Team. (2026). ERA Calculator — Earned Run Average [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/earned-run-average-calculator
TG we-Calculate Editorial Team. "ERA Calculator — Earned Run Average." TG we-Calculate. 2026. https://we-calculate.com/calculator/earned-run-average-calculator.
TG we-Calculate Editorial Team, "ERA Calculator — Earned Run Average," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/earned-run-average-calculator
@misc{wecalculate_earned_run_average_calculator, title = {ERA Calculator — Earned Run Average}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/earned-run-average-calculator}}, year = {2026}, note = {TG we-Calculate} }
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