Isolated PowerISO
ISO stands for isolated power in baseball. Extra bases per at-bat: slugging percentage with the singles taken out, so it measures power alone.
How ISO is calculated
ISO = SLG − AVG = (2B + 2 × 3B + 3 × HR) ÷ AB
A .300 hitter with no power and a .230 hitter with 40 home runs can post the same slugging percentage; ISO pulls them apart. League-wide it has sat near .160 in recent seasons, and .250 is elite.
What counts as a good ISO?
Half of the 241 qualified MLB players in 2026 were at or below .162. Clearing .229 put a season in the top tenth of the league.
- Median
- .162
- Top 10%
- .229
- Leader
- .298
By position, the median was .186 for 1B, .171 for DH, .168 for C, .167 for LF, .159 for RF and .156 for CF.
Qualified: 300+ AB, non-zero, 2026 regular season.