What is slugging percentage?
SLG is total bases per at-bat: it weights a double 2, a triple 3 and a homer 4, answering 'how much power is in this bat?'. League average sits around .420–.440 in the modern run environment.
How the calculator works
Total bases = 1B + 2×2B + 3×3B + 4×HR; SLG = TB ÷ AB. The tool also returns ISO (SLG − AVG), the pure power measure that strips out batting average.
Common use cases
- Fantasy power-category planning
- Comparing sluggers with different averages
- Tracking a prospect's power development
Formula & context
.500+ is excellent, .450 is solid, and .350 is a light-hitting middle infielder. ISO above .250 is MVP-tier power.
SLG vs ISO vs OPS
The three power stats answer different questions. SLG blends hit rate with power — a .290 singles hitter can out-slug a .230 hitter who only hits homers. ISO strips the average out entirely and shows raw extra-base muscle. OPS adds OBP to SLG for a full offensive picture. Use SLG for pure per-at-bat production, ISO to isolate power, and OPS for the headline number.
Sabermetric note
OPS overweights OBP slightly less than it should (on-base is worth more per point than slugging), which is why wOBA exists — it weights each outcome by actual run value. For fantasy purposes SLG and ISO remain perfectly serviceable.
Frequently Asked Questions
What is a good SLG?
.470+ is above average; .500+ is excellent power.
What is ISO?
Isolated power: SLG minus AVG — extra bases per at-bat, the cleanest power number.
Why don't walks count?
SLG measures per-at-bat power; walks are credited in OBP.
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