# Wavelength to Energy Calculator

With our wavelength to energy calculator, you can easily **find the amount of energy a photon carries by simply inputting the wavelength of its electromagnetic radiation**.

In this short text, we will introduce you to the **photon energy equation** and its relation with its wavelength.

By the end, you will have learned how to calculate energy from wavelength and convert **nm to eV** in no time!

## What are photons? Photon energy equation

Photons are particles of light. They have no mass, but they do have energy and momentum (see our photon energy calculator). The amount of energy a photon has is directly related to its wavelength.

By the **energy-momentum** relation, photons are *relativistic particles* since they travel at the speed of light.

💡 You can read more about these relativistic effects in our relativistic kinetic energy calculator.

### Photon energy equation

The relationship between a photon's energy and its wavelength can be expressed by the following equation:

where:

- $E$ is the energy of the photon (in joules).
- $h$ is Planck's constant ($6.62 \times 10^{-34} \ \text{m}^2\ \text{kg/s}$).
- $c$ is the speed of light in a vacuum ($3.00 \times 10^8 \ \text{m/s}$).
- $\lambda$ is the wavelength of the photon (in meters).
*These are***SI**units, but you can input all these variables in any unit with our wavelength to energy calculator, including**nm**and**eV**.

## How to convert between wavelength and energy of a photon

So, how do you calculate the energy from the wavelength of a photon? Use the equation above and input the **wavelength** of the photon's electromagnetic radiation. The result will be the **energy** the photon is carrying.

You can also easily switch from **nm to eV** with this wavelength to energy calculator. Simply select these units in the dropdown list next to each field.

If you want to convert *energy to wavelength* instead, you can either leave the wavelength field empty for our calculator to fill it for you (after inputting the photon's energy) or use the following formula: