Convert mil to mm

1 mil = 1/1000 inch = 0.0254 mm. The name is a contraction of milli-inch, and it is also called a thou. It has nothing to do with the metric prefix milli, so do not confuse a mil with a millimetre.

PCB CAD tools differ in their default units, so this conversion comes up constantly when handing over design data or writing fabrication notes.

A "100 mil pitch" connector is the same as a 2.54 mm pitch part.