You can set the units for all Graphical Sheets.
The possible units are:
•
Mil/Thou.
•
Inches
•
Microns
•
MM
•
CM
•
Meters
To set the units for a sheet click on the appropriate button in the 
Tools ribbon button group.
Set Design Settings to Imperial (Inches). This will set snap and grid spacing to 0.1" for all schematics and the PCB. Units will be set to inches for all schematics and the PCB. This will apply to all new projects. Existing schematic symbols and wires will be snapped to the new grid.
Set Design Settings to Metric. This will set snap and grid spacing to 2 mm for all schematics and to 1 mm for the PCB. Units will be set to cm for all schematics and to mm for the PCB. This will apply to all new projects.