Body fat scale mainly uses the principle of bioelectrical impedance measurement of BIA(Bio-impedanceanalysis) to measure our body fat. That is, when the human body stands on the electrode plate of the body fat scale, the body fat scale will send out a weak current through the electrode plate and form a closed circuit with the human body. This circuit will pass through muscles, fat and other parts of the human body, but only muscles and water in the human body can conduct electricity, but fat can't. At this time, the body fat will get an electrical impedance value according to the strength of the current in this closed circuit, and then calculate the prepared body fat according to the gender, age, height and weight of the tester.