The Boltzmann constant, and therefore entropy, have dimensions of energy divided by temperature, which has a unit of joules per kelvin (J⋅K) in the International System of Units (or kg⋅m ⋅s ⋅K in terms of base units). The entropy of a substance is usually given as an intensive property — either entropy per unit mass (SI unit: J⋅K ⋅kg) or entropy per unit amount of substance (SI unit: J⋅K ⋅mol).