A customary unit of measurement used primarily in North America to specify the thickness of materials like plastic sheeting, paint coatings, and wire diameters. One mil equals 0.001 inches or 25.4 micrometres. Machinists often call this same measurement a thou, while mil is preferred in manufacturing, packaging and printed circuit board design.
The specs call for a 6 mil poly vapor barrier under the concrete slab.
Do not confuse a mil with a millimetre. A millimetre is nearly forty times thicker than a mil.
Also heard as
- thou
Related terms
Same word, different worlds
One thousandth of an inch (25.4 micrometers), the usual North American unit for coating thickness.
Powder CoatingOne thousandth of an inch, exactly 25.4 microns, the everyday unit for coating thickness in North America.
GeosyntheticsOne thousandth of an inch, the unit North American crews use for geomembrane thickness.
Auto Repair & CarsThe dashboard warning light that indicates a fault detected by the engine control module.