Length Unit Converter
About Length Units
Length is a measure of distance. In the International System of Units (SI), the base unit of length is the meter (m), defined as the distance traveled by light in vacuum in 1/299,792,458 of a second. Common metric prefixes include kilo- (×1000), centi- (×0.01), and milli- (×0.001). While metric units are used globally in science and most countries, imperial units like miles, yards, feet, and inches remain common in the US and a few other regions.
Did You Know?
A light year is a unit of astronomical distance defined as the distance that light travels in one Julian year (365.25 days). It equals approximately 9.46 trillion kilometers or 5.88 trillion miles. Astronomers also use other units like the astronomical unit (AU, average Earth-Sun distance) and parsec (about 3.26 light years) for cosmic measurements. Despite its name, a light year measures distance, not time!