sensitive ears earrings

MM to Inches: 

There are 25.4 millimeters per 1 inch.

To convert millimeters to inches, simply take the millimeter measurement and divide it by 25.4. 

Example: You have a 12mm earring and you want to know the size in inches:

12 divided by 25.4 = 0.47 (which makes your earring almost ½ inch).