Kilometer to Millimeter Converter

About this conversion

The kilometer (km) is a unit of length in the metric (SI), commonly used for road and highway distances and geographic measurements. The millimeter (mm) belongs to the metric (SI) and is typically found in measurements related to engineering and manufacturing tolerances and bolt and screw dimensions. By definition, one kilometer is one thousand meters. One millimeter is one thousandth of a meter (0.001 m). The conversion factor between these two units is 1000000: multiplying any value in km by this number gives the equivalent in mm. For example, 10 km equals 10000000.0000 mm. Going the other direction, 1 mm equals 0.000001 km. Adopted alongside the metric system, the kilometer became the standard unit for land distance in most countries by the 20th century.