Convert mm to inches

Millimeter

Definition
A millimeter (symbol: mm) is an SI unit of length equal to one-thousandth of a meter (0.001 m). In terms of fundamental constants, it corresponds to the distance light travels in 1/299 792 458 000 of a second.

Ursprünge
The prefix milli- (Latin mille, “thousand”) denotes a factor of 10⁻³ in the metric system. While the meter itself was once defined by a physical platinum-iridium bar, today the meter—and therefore the millimeter—is tied to the fixed speed of light. Despite these shifts, the proportional relationship (1 mm = 0.001 m) has remained constant.

Moderne Nutzung
Millimeters are ubiquitous wherever fine precision is needed: engineering tolerances, technical drawings, machining parts, paper sizes, and map scales all frequently rely on millimeter measurements.

Inch

Definition
An inch (symbol: in) is a length unit in the Imperial and U.S. customary systems. Since 1959, one inch is exactly 25.4 mm. Each foot contains 12 inches, and each yard contains 36 inches.

Ursprünge
Derived from the Latin uncia (“one-twelfth”), early definitions of the inch included three barleycorns laid end-to-end or the average width of three thumbs. Eventually, it was standardized against the international yard.

Moderne Nutzung
Inches remain standard in the U.S., Canada, and the U.K. for construction, woodworking, hardware dimensions, and electronic display measurements (e.g., screen diagonals).

Millimeter → Inch Conversion Table

Wie man konvertiert

• 1 mm = 0.0393700787 in

• 1 in = 25.4 mm

Beispiel

To convert 15 mm to inches:

15 mm × 0.0393700787 in/mm = 0.5905511811 in