A "mil" is a unit of measurement that equals one-thousandth of an inch, or 0.001 inch. It is commonly used to measure the thickness of plastic sheeting and films. One mil also equals 0.0254 millimeters. For example, a credit card is around 30 mils thick, and a common deck of playing cards, including the box, is 15 mils thick
. In the US Customary System, a "mil" is also a unit of length equal to 1/1000 of an inch, which is approximately 0.03 millimeters
