Convert between mils (thousandths of an inch) and millimeters in either direction — a common conversion for wire gauges, coating thicknesses, and plastic film.
How it works
A mil is one-thousandth of an inch, and the international inch is exactly 25.4 mm, so 1 mil = 0.0254 mm exactly. Enter a value in either field and the other updates instantly.
What this does not include
This is the “mil” meaning a thousandth of an inch — not to be confused with the metric “millimeter” abbreviation, or with a “mil” as a unit of angle used in artillery and optics, which is a completely different measurement.
How to use this calculator
- Enter a value in mils or millimeters.
- The other field updates automatically.
Where is “mil” commonly used?
Wire diameter (especially in the US), plastic sheeting and film thickness, and some coating and paint specifications are commonly given in mils.
Is “mil” the same as “thou”?
Yes — “thou” is a British term for the same unit, one-thousandth of an inch.
How thick is 1 mil in practical terms?
About the thickness of a typical sheet of household plastic wrap — thin enough that mils are almost always the more convenient unit than fractions of an inch for this kind of measurement.
