Chain
The chain (symbol ch) is an imperial and US customary unit of length equal to 66 feet, 22 yards, or exactly 20.1168 metres. Introduced in 1620 by English mathematician Edmund Gunter, Gunter's chain comprised 100 links and revolutionized land surveying. It laid the foundation for modern land division in English-speaking nations, where 10 square chains defined the area of one acre, a standard still reflected in historical property deeds.
Metric
- Kilometre (km)0.02
- Metre (m)20.12
- Decimetre (dm)201.17
- Centimetre (cm)2,011.68
- Millimetre (mm)20,116.8
- Micrometre (µm)20,116,800
- Nanometre (nm)2.01×10¹⁰
- Angstrom (Å)2.01×10¹¹
Nautical
- Nautical mile0.01
- Fathom11
Astronomical
- Parsec (pc)6.52×10⁻¹⁶
- Light year2.13×10⁻¹⁵
- Astronomical unit (au)1.34×10⁻¹⁰
- Light minute1.12×10⁻⁹
- Light second6.71×10⁻⁸