Length Conversion - Metric, Imperial, and Historical Units

The Length Conversion Calculator enables you to convert between various length units, including metric, imperial, and lesser-known historical units. Some units, like furlongs, chains, and perches, are no longer widely used but are included for their historical significance. This calculator allows for high precision with up to 20 decimal places, offering accurate conversions for standard and specialized measurements.

Metric Units:

Yoctometres (ym): A length unit mainly used in scientific measurements at tiny scales, such as particle physics.
Zeptometres (zm): A unit used for very small distances in quantum physics.
Attometres (am): This unit is used in high-energy physics to describe subatomic particle sizes.
Femtometres (fm): Commonly used to measure the sizes of atomic nuclei.
Picometres (pm): Often used to measure atomic dimensions or wavelengths of electromagnetic radiation.
Nanometres (nm): A unit frequently used in nanotechnology to measure wavelengths of light.
Micrometres (µm): A unit used in biology and materials science to measure tiny particles and microorganisms.
Millimetres (mm): A standard used in everyday measurements for small distances.
Centimetres (cm): Used in daily measurements for shorter lengths, such as the width of objects.
Decimetres (dm): A unit occasionally used for intermediate-length measurements.
Metres (m): The base unit of length in the metric system, commonly used worldwide for everyday length measurements.
Decametres (dam): Equal to 10 meters, used for medium-length measurements.
Hectometres (hm): A unit equal to 100 metres used for land area measurements in hectares.
Kilometres (km): Equal to 1,000 meters, used to measure distances between locations on land.
Megametres (Mm): A unit equal to 1 million meters, used to describe large-scale distances, often in astronomy.
Gigametres (Gm): Equal to 1 billion meters, used for astronomical distances within a planetary system.
Terametres (Tm): A unit used for large distances, such as between stars.
Petametres (Pm): Useful for interstellar distance measurements.
Exametres (Em): Used for large cosmic distances.
Zettametres (Zm): Used in theoretical cosmology for extreme distances.
Yottametres (Ym): The largest unit in the metric system used to describe distances across the observable universe.

Imperial and US Customary Units:

Inches (in): A unit of length commonly used in the US and UK, equal to 1/12 of a foot or 2.54 centimetres.
Feet (ft): A unit of length equal to 12 inches or 0.3048 metres, widely used in the US for measuring short distances.
Yards (yd): A length equal to 3 feet or 0.9144 metres, often used for measuring medium distances such as in sports fields.
Miles (mi): A length equal to 5,280 feet or 1.609 kilometres, used to measure longer distances, especially in the US and UK.
Furlongs (fur): A length equal to 1/8 of a mile or 201.168 metres, traditionally used in horse racing and land measurements.
Chains (ch): A unit of length equal to 66 feet or 20.1168 metres used in land surveying.
Links (li): A unit equal to 1/100th of a chain or 0.201168 meters, also used in surveying.
Rods (rd): A unit of length equal to 16.5 feet or 5.0292 metres, historically used in land measurement.
Leagues (lea): A unit of length equal to 3 miles or 4.828 kilometres, used in old English and American systems.
Nautical Mile (NMI): A unit of length equal to 1,852 metres used in maritime and air navigation.
Cable Lengths (cbl): A unit of length equal to 1/10 of a nautical mile or 185.2 metres, used in maritime measurements.
Hands (hh): A unit used to measure the height of horses, equal to 4 inches or 0.1016 meters.
Thou (th): Also known as a mil, this unit is equal to 1/1,000th of an inch or 0.0254 millimetres and is used in engineering.

French Units (Quebec):

French Feet (Quebec): A traditional French unit used in Quebec, approximately 0.3248 meters.
Arpents (Quebec): A unit of land measurement equal to approximately 58.47 metres used in rural Quebec.
French Perches (Quebec): A traditional unit equal to approximately 3.79 metres used for smaller distance measurements in early Quebec.

Scientific and Specialized Units:

Angstroms (Å): A unit of length used to express atomic-scale distances such as bond lengths.
Atomic Unit of Length (a0): A natural unit of length used in atomic physics.
Natural Unit of Length: A unit based on fundamental physical constants used in quantum field theory.
Planck Length (LP): The smallest theoretical unit of length used in quantum mechanics and cosmology.

Astronomical Units:

Astronomical Unit (au): A standard unit of distance in astronomy, approximately equal to the mean distance between the Earth and the Sun (about 149.6 million kilometres).