The Stefan-Boltzmann constant σ\sigmaσ is a constant that appears in the Stefan-Boltzmann law. In SI units, it is σ=5.67×10−8 Wm2 K4\sigma=5.67\times10^{-8}\ \frac{\text{W}}{\text{m}^{2}\text{ K}^{4}}σ=5.67×10−8 m2 K4W