Isolated power
Sabermetric baseball statistic
title: "Isolated power" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["batting-statistics"] description: "Sabermetric baseball statistic" topic_path: "science/mathematics" source: "https://en.wikipedia.org/wiki/Isolated_power" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Sabermetric baseball statistic ::
In baseball, isolated power or ISO is a sabermetric computation used to measure a batter's raw power. One formula is slugging percentage minus batting average.
ISO = SLG - AVG
= \frac{\mathit{TB} - H}{AB}
= \frac{(\mathit{1B}) + (2 \times \mathit{2B}) + (3 \times \mathit{3B}) + (4 \times \mathit{HR})}{AB} - \frac{H}{AB}
= \frac{(\mathit{1B}) + (2 \times \mathit{2B}) + (3 \times \mathit{3B}) + (4 \times \mathit{HR}) - (\mathit{1B} + \mathit{2B} + \mathit{3B} + \mathit{HR})}{AB}
= \frac{(\mathit{2B}) + (2 \times \mathit{3B}) + (3 \times \mathit{HR})}{AB}
The final result measures how many extra bases a player averages per at bat. A player who hits only singles would thus have an ISO of 0. The maximum ISO is 3.000, and can only be attained by hitting a home run in every at-bat.
The term "isolated power" was coined by Bill James, but the concept dates back to Branch Rickey and his statistician Allan Roth.
References
- Baseball Prospectus Glossary
- Baseball Simple : Isolated Power (ISO) Calculator
- FanGraphs Sabermetrics Library
References
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