joule per kelvin
SI coherent derived unit whose name and symbol includes an SI coherent derived unit with a special name and symbol
Name | Symbol | Quantity | Expressed in terms of SI base units | |
joule per kelvin | J/K | heat capacity, entropy |
kg m2 s−2 K−1 | ![]() |
DefinitionThe joule per kelvin, symbol J/K, is the SI coherent derived unit of heat capacity, and entropy. |
The fixed numerical value of the Boltzmann constant, k, is defined to be exactly 1.380 649 × 10‑23 when expressed in the unit joule per kelvin, symbol J K-1.
Inverting this relation gives an exact expression for the joule per kelvin in terms of the SI defining constant k :
The effect of this definition is that one joule per kelvin is exactly 1⁄1.380 649 × 10−23 of the Boltzmann constant.