The scale uses bioelectrical impedance analysis (BIA), sending a safe, weak electrical current through your body when you stand barefoot on the platform. The current measures tissue resistance to calculate body fat percentage, skeletal muscle mass, bone mass, and body water percentage. The technology is the same used by many professional athletic programs.

No, but the scale works best within the Garmin ecosystem. You can use it with just the free Garmin Connect app on your smartphone, but if you already own a Garmin watch, all your body composition data appears alongside your activity, sleep, and training metrics for a complete performance picture.

The Index S2 provides consistent, reliable body composition measurements that are excellent for tracking trends over time. While no at-home scale matches the precision of DEXA scans or hydrostatic weighing, the Index S2 delivers accuracy within 3-5% when used consistently under the same conditions. The real value is tracking changes across training cycles.

The scale works best on hard, flat surfaces like tile, hardwood, or laminate flooring. If you need to use it on carpet, Garmin includes four adjustable feet/risers that elevate the scale for more accurate readings on soft surfaces.