If you are using metric system and if you are more comfortable with cm, mm instead of inches then you might need to change this setting when you work with images in Office documents or presentations.
This is done very easy by changing your System regional settings:
1. Search for “Regional” or go to Regional Settings in Control Panel
2. Click on “Additional Settings”
3. In “Measurement System“, change from “US” to “Metric”
And that should be all. Select again your image in Word, Excel, PowerPoint and you will get the size values in Metric units.