: Muscle contains a high percentage of water and conducts electricity easily. Fat has a low water content and acts as an insulator, resisting the current.

: The scale measures this resistance (impedance) and combines it with your age, height, gender, and weight to estimate your body fat percentage. Top Body Fat Scale Recommendations (2026)

Body fat scales use . When you step on the scale, it sends a very low, painless electrical current through your body.