How thick is 3.5 mil?

Three and a half mil (3.5 mil) is equivalent to 0.0035 inches or 0.0889 millimeters. The term "mil" refers to one-thousandth of an inch, commonly used to measure the thickness of materials like plastic sheeting or film. Therefore, 3.5 mil is a relatively thin material, often used in applications such as packaging or protective covers.