Calculator for Ideal Black Bodies

Calculate black body radiation with the Stefan-Boltzmann law

An ideal black body is a theoretical model for something which absorbs every incoming electromagnetic radiation. Practically, this model is used e.g. for stars and furnaces. The radiation of a black body can be calculated with the Stefan-Boltzmann law.
Please enter two values and select the units. The third value will be calculated.
The formula is P = σ * A * T⁴ with the Stefan-Boltzmann constant σ = 5,670367 * 10^-8 W / m² / K⁴

Example: the Sun with its surface area of 6087799000000 square kilometers and surface temperature of 5778 Kelvin has a radiant power of 384.75 yottawatts (YW, 10²⁴ watts). The radiant power per square meter is 63.2 megawatts.

Surface area A:
Temperature T:
Power P: