SI base unit: kelvin (K)
The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be
This definition implies the exact relation k =
![](/documents/20126/42149531/SI-equation-K-1-EN.jpg/c0b76eec-822b-a937-18ef-fd9815286bea?t=1594242731271)
which is equal to
![](/documents/20126/42149531/SI-equation-K-2-EN.jpg/da1ccbc4-a41c-c207-d6ec-e149871f0526?t=1594242686156)
The effect of this definition is that one kelvin is equal to the change of thermodynamic temperature that results in a change of thermal energy k T by
See:
SI Brochure - Appendix 2
SI Brochure - excerpts from Appendix 4