The Stefan-Boltzmann constant is a physical constant relating the power radiated from a black body to its temperature according to the Stefan-Boltzmann law (i.e., Stefan-Boltzmann equation, different from the Boltzmann equation): the energy radiated by a black body is proportional to its surface and the fourth power of its temperature:
j* = σT4
In SI units, it is:
σ = 5.67036713×10-8 W m-2 K-4
It can be derived from the Boltzmann constant, Planck constant, and the speed of light.