The Loschmidt constant is given by the relationship:

The precision to which the Loschmidt constant is currently known is limited entirely by the uncertainty in the value of the gas constant.

Being a measure of number density, the Loschmidt constant is used to define the amagat, a practical unit of number density for gases and other substances:

In the CODATA set of recommended values for physical constants, the Loschmidt constant is calculated from the gas constant and the Avogadro constant: