Our custom clear labels are 5.7 mils (0.0057 inches or 144 microns) thick. Keep in mind, mil is not short for millimeter. Mil is a commonly used measurement for products like labels and stickers. It's equivalent to 1/1000 of an inch. You can read more about using mil as a form of measurement on Wikipedia.
Without the paper backing, the clear labels are approximately 2.5 mils thick, including adhesive.
Label: 2.0 mil (.002 inches or 0.051 mm +/- 10%) Adhesive: 0.5 mil (.0005 inches or 0.0127 mm +/-10%) Backing: 3.2 mil (.0032 inches or 0.081 mm+/- 10%)