Millimeters to Inches converter

Convert millimeters (mm) to inches (in) — results update instantly as you type.

Millimeters to Inches

To0.03937

1 mm = 0.03937008 in

How to convert Millimeters to Inches

Length is the most everyday measurement there is — yet the world still splits between the metric system (millimeters, centimeters, meters, kilometers) and the imperial system (inches, feet, yards, miles). This converter bridges both, plus nautical miles used in aviation and shipping.

Every length unit is defined as an exact multiple of the meter, the SI base unit. An inch is exactly 0.0254 meters and a mile is exactly 1609.344 meters, so converting between any two units is a single multiplication — no approximations involved.

Formula

mm × 0.0393700787 = in

Multiply your millimeters value by 0.0393700787 to get inches. For the reverse, divide by the same factor.

Millimeters to Inches conversion table

MillimetersInches
1 mm0.03937 in
2 mm0.07874 in
5 mm0.19685 in
10 mm0.393701 in
25 mm0.984252 in
100 mm3.937008 in

Common use cases

  • Converting body height between centimeters and feet/inches
  • Road trip distances between kilometers and miles
  • Screen sizes, fabric, and DIY measurements in inches vs centimeters
  • Marine and aviation distances in nautical miles

Frequently asked questions

Exactly 2.54 centimeters. The inch has been defined as precisely 25.4 millimeters since the international yard and pound agreement of 1959.