Enter the wavelength into the calculator to determine the Energy from Wavelength. 

Wavelength to Energy Calculator

Enter one value to calculate the other

Energy from Wavelength Formula

The following equation is used to calculate the Energy from Wavelength.

E = h*c / λ
  • Where E is the Energy from Wavelength (Joules)
  • λ is the wavelength (m)
  • h is the Planck’s Constant (6.626176 x 10-34 joule-seconds.)
  • c is the speed of light (299 792 458 m/s)

To calculate energy from a wavelength, divide the product of Planck’s Constant and the speed of light by the wavelength.

Wavelength to Photon Energy Conversion Table (E = hc/λ; hc/e ≈ 1239.842 eV·nm)
Wavelength (nm) Energy (eV)
10012.398
121.610.197
2006.199
2544.881
2804.428
3653.397
4053.061
4502.755
4882.541
5322.332
5892.105
6331.959
6501.907
7001.771
8081.535
8501.459
9051.369
10641.165
13100.946
15500.800
Photon energy in vacuum: E = (h·c)/λ. Constants: h = 6.62607015×10^-34 J·s, c = 299,792,458 m/s. Shortcut: E(eV) ≈ 1239.842 / λ(nm).

What are the units for Energy from Wavelength?

The most common units for Energy from Wavelength are Joules.

How to Calculate Energy from Wavelength?

Example Problem:

The following example problem outlines the steps and information needed to calculate the Energy from Wavelength.

First, determine the wavelength. In this example, the wavelength is determined to be 150 (m).

Finally, calculate the Energy from Wavelength using the formula above: 

E = h*c / λ

Inserting the values from above and solving the equation with the imputed values gives: 

E = 299 792 458*6.626176 x 10^-34 / 150 = 1.3243184e-27 (Joules)