Light Year to Kilometer Converter

About this conversion

The light-year (ly) is a unit of length in the astronomical, commonly used for distances to nearby stars and sizes of galaxies. The kilometer (km) belongs to the metric (SI) and is typically found in measurements related to road and highway distances and geographic measurements. By definition, one light-year is the distance light travels in one Julian year in a vacuum, approximately 9.461 × 10¹⁵ meters. One kilometer is one thousand meters. The conversion factor between these two units is 9460700000000: multiplying any value in ly by this number gives the equivalent in km. For example, 10 ly equals 94607000000000.0000 km. Going the other direction, 1 km equals 0 ly. Adopted alongside the metric system, the kilometer became the standard unit for land distance in most countries by the 20th century.