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CGS is the centimetre-gram-second standard system of units of measurement.

This system is rarely used nowadays, the SI units having largely taken over.

CGS Base Units

CGS Base Units
Name Unit symbol Dimension Symbol
centimetre $\mathrm{cm}$ Length $l$
gram $\mathrm g$ Mass $m$
second $\mathrm s$ Time $t$

CGS Derived Units


The dyne is the CGS unit of force.

It is defined as being:

The amount of force required to accelerate a mass of one gram at a rate of one centimetre per second squared.
\(\ds \) \(\) \(\ds 1\) dyne
\(\ds \) \(=\) \(\ds 10^{-5}\) newtons


The erg is the CGS unit of energy:

It is defined as being:

the energy transferred to (or work done on) a body when a force of $1$ dyne acts on that body in the direction of the force's motion through a distance of $1$ centimetre.


$1 \, \mathrm {erg} = 1 \, \mathrm {dyn} \, \mathrm {cm}$
\(\ds \) \(\) \(\ds 1\) erg
\(\ds \) \(=\) \(\ds 10^{-7}\) joules

Also known as

The CGS system is also known as the Gaussian system, for Carl Friedrich Gauss.

This term is used usually in the context of atomic physics and solid-state physics, where their scale is more convenient than that of SI units.

Also see