Isolated Power (ISO) distills a hitter’s raw pop by stripping away routine singles and focusing purely on extra bases.
It does this by subtracting batting average from slugging percentage, leaving a number that tells you how often a player turns contact into doubles, triples, or homers.
Use the quick calculator below to explore how small changes in slugging or average can dramatically move a player’s perceived thump.
Frequently Asked Questions
What does ISO measure?
ISO isolates a hitter’s true power by showing how many extra bases he gains per at bat.
Singles are ignored, making the metric a quick read on doubles, triples, and homers.
Is a higher ISO always better?
Generally yes; a bigger number means more extra-base pop.
Still, roster needs, ballpark factors, and strikeout rates can influence how valuable raw power is to a club.
What is a good ISO benchmark?
Roughly .140 is league average.
Anything above .200 signals plus power, while .250 or higher is elite territory.
Can ISO be negative?
No. Because slugging percentage is never lower than batting average, the subtraction cannot yield a negative value.
Does ISO account for stolen bases?
No. ISO looks only at results of batted balls and ignores speed metrics like steals.