Centimetre–gram–second system of units
Metric system variant using centimetre, gram, and second.
The centimetre–gram–second system of units (CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unambiguously derived from these three base units, but there are several different ways in which the CGS system was extended to cover electromagnetism. The CGS system has mainly been supplanted by the MKS system based on the metre, kilogram, and second, which was in turn extended and replaced by the International System of Units (SI). In many fields of science and engineering, SI is the only system of units in use, but CGS is still prevalent in certain subfields.
- field
- Systems of measurement
- known_for
- Base units of centimetre, gram, and second; multiple electromagnetic variants including Gaussian units
Lore & Background
Gauss chose the units of millimetre, milligram and second. unit of ...'.
Reader's Guide
The CGS system was historically significant as the first coherent metric system for science, but its sizes proved inconvenient for practical use. Starting in the 1880s, and more significantly by the mid-20th century, CGS was gradually superseded internationally for scientific purposes by the MKS system, which in turn developed into the modern SI standard. Since the international adoption of the MKS standard in the 1940s and the SI standard in the 1960s, technical use of CGS units has gradually declined worldwide. CGS units have been deprecated in favour of SI units by NIST, as well as organisations such as the American Physical Society and the International Astronomical Union. SI units are predominantly used in engineering applications and physics education, while Gaussian CGS units are still commonly used in theoretical physics, describing microscopic systems, relativistic electrodynamics, and astrophysics. The units gram and centimetre remain useful as noncoherent units within the SI system.
Did You Know?
- Gaussian CGS units are the most widely used CGS variant in modern scientific literature.
More in Metrology 1-24
Elsewhere in the Metrology universe
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record