Blackbody Peak Wavelength Calculator Formula

Understand the math behind the blackbody peak wavelength calculator. Each variable explained with a worked example.

Use the Blackbody Peak Wavelength Calculator

Formulas Used

Peak Wavelength

peak_wavelength = 2.898e-3 / temperature

Peak Wavelength (nm)

peak_nm = 2.898e-3 / temperature * 1e9

Peak Frequency

peak_frequency = 2.998e8 / (2.898e-3 / temperature)

Variables

VariableDescriptionDefault
temperatureTemperature(K)5778

How It Works

Wien's Displacement Law

The wavelength at which a blackbody emits most intensely is inversely proportional to its temperature.

Formula

lambda_max = b / T

  • *b* = 2.898 x 10^-3 m K (Wien displacement constant)
  • *T* = temperature in kelvin

    • Hotter objects peak at shorter (bluer) wavelengths; cooler objects peak at longer (redder) wavelengths.

    Worked Example

    The Sun's surface at 5778 K.

    temperature = 5778
    1. 01lambda_max = b / T
    2. 02lambda_max = 2.898e-3 / 5778
    3. 03lambda_max = 5.015e-7 m = 501.5 nm
    4. 04This falls in the green part of the visible spectrum.

    Ready to run the numbers?

    Open Blackbody Peak Wavelength Calculator