The short answer is “about as thick as a playing card.” But if you want to get all technical, the answer is 23 mils thick. That’s 0.023 inches or a little more than half of a millimeter.A mil is a unit of measurement used to measure paper thickness. It is equal to one-thousandth of an inch. Our tile stickers are made from 20 mil adhesive vinyl and coated in 3 mils of protective laminate. Other cheaper tile stickers on the market use vinyl that is only 13 mils thick.  For reference, here are some examples of common paper thickness:Photo film – 7 milPrinter paper – 8 milTraditional glossy photo paper – 10 milCardboard – 22 mil