- Press and hold the unit button at the back of your scale for a few seconds.
- Press the unit button again to change the unit.
- Make sure the correct unit is displayed on the screen of your scale. If not, press the unit button again.
The unit change is confirmed a few seconds after you stop pressing the button.
https://support.withings.com/hc/en-us/sections/6212651181969-Smart-Body-Analyzer
https://support.withings.com/hc/en-us/sections/200499328-Tutorials