How do you convert thousands of an inch into millimeter?

Answer 1

If you mean for wire, the following link has both an exact formula, and a close approximation (with a simpler formula): http://en.wikipedia.org/wiki/American_wire_gauge#Formula

Answer 2

To convert thousandths of an inch to millimeters, you can multiply the measurement in thousandths of an inch by 0.0254. This conversion factor accounts for the difference in the unit sizes between inches and millimeters.

Answer 3

.001 inch=about.004mm