inch to mm Converter - Inch to Millimeter

Conversion derivation

Express both inch and mm in the same base unit m (meter), then cancel the shared base unit.

1. 1

   Rewrite inch in the base unit

   $$1\mathrm{inch}=0.0254\mathrm{m}$$
2. 2

   Rewrite mm in the base unit

   $$1\mathrm{mm}=0.001\mathrm{m}$$
3. 3

   Forward conversion

   $$\begin{array}{rl}1\mathrm{inch}& =\frac{0.0254\cancel{\mathrm{m}}}{0.001\cancel{\mathrm{m}}}\times 1\mathrm{mm}\\ & =\frac{0.0254}{0.001}\mathrm{mm}\\ & =25.4\mathrm{mm}\end{array}$$
4. 4

   Reverse conversion

   $$\begin{array}{rl}1\mathrm{mm}& =\frac{0.001\cancel{\mathrm{m}}}{0.0254\cancel{\mathrm{m}}}\times 1\mathrm{inch}\\ & =\frac{0.001}{0.0254}\mathrm{inch}\\ & =0.03937007874\mathrm{inch}\end{array}$$