IntermediateHitting
ISO
Isolated Power
Slugging percentage minus batting average. Singles drop out, leaving only the extra bases per at-bat.
.1562026 MLB average (2025: .159)
Simple explanation
Take a .300 hitter slugging .400 and a .250 hitter slugging .450. Their ISOs are .100 and .200. The first one gets more hits, but the second one hits the ball farther.
It's the same as counting a single as 0, a double as 1, a triple as 2 and a homer as 3. Anything above .200 marks a genuine power hitter.
Benchmarks
- .114
- Bottom 10%
- .168
- Median
- .238
- Top 10%
Distribution of the 135 qualified hitters in 2026.
Detailed explanation
ISO = SLG − AVG = (2B + 2×3B + 3×HR) ÷ AB
- 2B
- doubles
- 3B
- triples
- HR
- home runs
- AB
- at-bats
There's no park or league adjustment. A hitter-friendly home park pushes it up, and in a year when the ball doesn't carry, the whole league drops.
The same ISO doesn't mean the same hitter. A .250/.450 hitter and a .350/.550 hitter both come out at .200, and the second one is far better. ISO tells you what kind of hitter someone is more than how good he is.
It needs a big sample. FanGraphs puts it at around 550 plate appearances before ISO starts predicting future ISO.