Here is a list of all common length units used in various measurement systems. These units span across different systems including Metric (SI), Imperial, US Customary, and other specialized units:
Metric System (SI Units)
Meter (m)
Kilometer (km)
Centimeter (cm)
Millimeter (mm)
Micrometer (µm)
Nanometer (nm)
Picometer (pm)
Femtometer (fm)
Angstrom (Å)
Light-year (ly)
Parsec (pc)
Imperial System
Inch (in)
Foot (ft)
Yard (yd)
Mile (mi)
Furlong (fur)
Rod (rd)
Chain (ch)
Link (li)
US Customary System
Inch (in)
Foot (ft)
Yard (yd)
Mile (mi)
Surveyor's Chain (ch)
Surveyor's Rod (rd)
Other Specialized Length Units
League (lea) - A unit used historically to measure distance, usually about 3 miles.
Astronomical Unit (AU) - The average distance between the Earth and the Sun (~149.6 million kilometers).
Nautical Mile (NM or nmi) - Used in maritime and air navigation; 1 nautical mile = 1.852 kilometers or 1.15078 miles.
Fathom (ftm) - Primarily used for measuring depth in oceans; 1 fathom = 6 feet.
Mil (thou) - A thousandth of an inch, used mainly in engineering and manufacturing.
Cubit (cu) - An ancient unit based on the length of the forearm.
Span - The distance between the tip of the thumb and the tip of the little finger, traditionally used in measuring.
Astronomical and Other Large Distance Units
Light Year (ly) - The distance that light travels in one year (~9.461 trillion kilometers).
Parsec (pc) - A unit of distance used in astronomy, equal to about 3.26 light-years.
Kiloparsec (kpc) - 1,000 parsecs.
Megaparsec (Mpc) - 1,000,000 parsecs.
These units serve various purposes and are used in different contexts such as astronomy, geography, engineering, and everyday life.