Lei de Wien (λ_máx)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
λ_max = b/T
About this calculator
The Wien's Law calculator determines the peak wavelength of blackbody radiation at a given temperature. The law states that λ_max is inversely proportional to absolute temperature T, with Wien's constant b = 2.898e-3 m·K. Simply enter the temperature in Kelvin to obtain the wavelength in meters.
This tool is useful in astrophysics, thermography, and thermal engineering. For example, to estimate star temperatures from their spectra or to adjust infrared sensors. The calculation is instant and requires no prior knowledge of the formula.
Cautions: the law applies only to ideal blackbodies. Real objects may have emissivity that shifts the peak. Also, temperature must be in Kelvin; incorrect conversions from Celsius or Fahrenheit lead to errors. For very high or low temperatures, check if the result lies in the expected electromagnetic spectrum range.
Frequently asked questions
Can I use Celsius or Fahrenheit for temperature?
No, the formula requires Kelvin. Convert to Kelvin first: K = °C + 273.15 or K = (°F + 459.67)/1.8.
What happens if I input a negative temperature?
Negative Kelvin temperatures are not physically possible. The calculation will return an invalid value.
Does Wien's law apply to any object?
It is exact for ideal blackbodies. For real objects, the peak can be approximated, but there may be shifts due to emissivity.
What is the unit of the result?
The wavelength is given in meters (m). To convert to nanometers, multiply by 1e9.