This app uses mathematical formulas to calculate blackbody radiation of an object at a particular wavelength and at a given temperature. It uses Planck’s Law to calculate spectral radiance and radiant exitance in watts and photons per second. Total radiance is calculated using Stefan's law. Introductory information is included for users who want to learn basic concepts, definitions and radiation principles. This simple tool can be used by engineers, scientists or students in the electro-optics and infrared fields. A list of physical constants and a table of emissivity values for various materials are provided.