EngiRef / Length conversion

Convert Millimeters to Inches (mm to in)

1 mm = 0.0393700787 in. Convert millimeters to inches with the exact factor, a common-values table and a free converter.

LengthSingle factor7 worked values

Conversion factor

in = mm × 0.0393700787

1 mm = 0.0393700787 in

Multiply by 0.0393700787 in to go from millimeters to inches, or divide by it to come back. The factor and every value below are computed by the same converter that runs at /convert, so this page and the tool cannot disagree.

mm to in table

Common millimeters values converted to inches
Millimeters (mm)Inches (in)
1 mm0.0393700787 in
2 mm0.0787401575 in
5 mm0.196850394 in
10 mm0.393700787 in
20 mm0.787401575 in
50 mm1.96850394 in
100 mm3.93700787 in

Every figure is computed at build time by the site’s own converter from the length unit registry. For a value that is not listed, put it into the interactive converter.

Frequently asked questions

How many inches are in one millimeter?

One millimeter is 0.0393700787 in, so 100 mm is 3.93700787 in.

What is the formula to convert millimeters to inches?

in = mm × 0.0393700787. Multiply the value in millimeters by 0.0393700787 to get inches.

How do I convert inches back to millimeters?

mm = in × 25.4, so 1 in is 25.4 mm. The in to mm page carries the same table in that direction.