Length Converter Tool

Length Conversion

Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system the base unit for length is the metre.

Length Units Explained

Here are some of the most common units of length you might encounter:

  • Meter (m): The base unit of length in the International System of Units (SI). Originally defined as one ten-millionth of the distance from the equator to the North Pole.
  • Kilometer (km): Equal to 1,000 meters. Commonly used for expressing distances between geographical places on land in most of the world.
  • Centimeter (cm): Equal to 1/100th of a meter. Often used in everyday measurements.
  • Millimeter (mm): Equal to 1/1000th of a meter. Used for engineering and precise measurements.
  • Inch (in): A unit of length in the British imperial and the United States customary systems of measurement. It is equal to exactly 25.4 mm.
  • Foot (ft): Equal to 12 inches.
  • Yard (yd): Equal to 3 feet or 36 inches.
  • Mile (mi): A British imperial and US customary unit of length, equal to 5,280 feet or 1,760 yards.

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Fun Fact: The meter is currently defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second. This definition fixes the speed of light in a vacuum at exactly 299,792,458 m/s.