In Word 2013, you can choose which of several available units to display on the Ruler. After all, sometimes you have to work on a document for someone who measures page margins, tab stops, and so on in a system of units that is different from yours. Changing the units of measurement on the Ruler in Word is very easy.
Click the Fillet (File).
In the list on the left, select Options (Options).
A dialog box will appear Word Options (Word Options). In the dialog box that opens, select from the list on the left Advanced (Additionally).
Scroll down to the section Display (Screen). Select the desired option from the dropdown list Show measurements in units of (Units).
Now the units of measurement of the Ruler have changed to those that you indicated.
If you do not see the Ruler, open the tab View (View) and in section Show (Show) check the box next to the option Ruler (Ambulance).
You can always easily change the system of measurement units of the Ruler to the desired one by opening the dialog box Word Options (Word Options) and selecting the appropriate units of measure.