Blackbody Radiation Calculator

The JavaScript calculator below will allow you to compute blackbody radiation using Planck's Law. The calculator is quite flexible. Simple enter any two values to compute the third. The checkboxes are automatically adjusted to indicate the parameters used as inputs. The graphs below the calculator are automatically updated.

Temperature:

 K

Wavelength:

   nm μm

Radiance:

 W/m²/sr/nm

You must have JavaScript enabled in your browser to work with this calculator.

---

DISCUSSION:

Planck's Law describes the spectral radiance at a specific wavelength of a blackbody at a given temperature. The three plots below show:

• Spectral radiance as a function of wavelength for the temperature specified in the calculator.
• Spectral radiance as a function of temperature for the wavelength specified in the calculator.
• Temperature as a function of wavelength for the spectral radiance specified in the calculator.

The first plot is the typical plot of Planck's Law. The second plot illustrates how the spectral radiance monotonically increases with temperature at any given wavelength. The third plot illustrates the potential combinations of temperature and wavelength that can produce a given spectral radiance.