BMI Application Guide: The BMI value is based on CM units (According to WTO Standard), users are required to enter centimeters of height. Step 1.If you need to use BMI function, press the unit conversion button at the bottom of the scale, convert to KG unit mode. Step 2.Press the ‘set’ button to input your height value in “CM” unit, then step onto the scale for 10 second,the weight (KG) and BMI value will will repeat for 3 times in turn. Step 3.If you are accustomed to using LB as the weight unit, please change back to the LB unit mode, but the height value must be set in centimeters before hand.