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Photon Energy Calculator

Photon Energy Calculator

Note: Please enter Wavelength or Frequency to calculate Photon Energy.

Wavelength (λ):


Frequency (f):


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An online photon energy calculator that allows you to calculate the energy of a photon from its wavelength (ƛ) & frequency (f). In simple words, with the ease of this online tool, you can explore the relationship between the frequency, wavelength and the energy. Keep reading to know about the energy of a photon equation (Planck’s equation), manual calculations and many other useful & interesting information.

But, let’s ahead to some basics.

Read on!

What is Planck’s equation?

The light travels in the small chunks called the photon. The energy carried by a single photon called the energy of a photon. It is directly proportional to its frequency & inversely related with the wavelength of photons. The relationship between these quantities described by the Max Planck in his equation as:

E = h*c/ƛ = h*f


  • h is the Planck’s constant
  • c is the speed of light
  • ƛ is the wavelength
  • f is the frequency

The Planck’s constant & speed of light in vacuum have definite values i;e

h = 6.6261 × 10^-34 Js

c = 299792458 m/s

Also, our online energy of a photon calculator considers these formulas and constants for the exact calculations. You can our online velocity calculator that helps you to calculate the speed/velocity of the moving object.

How to Find Energy of a Photon Manually (Step-by-Step):

Calculating the energy of a photon becomes very easy with this online photon energy calculator. So, here we an example of the manual calculation to determine the accurate results.


Determine the energy of photons that have a wavelength of 10m?


Step 1:

The energy of a photon formula is:

E = h*c/ƛ

Step 2:


ƛ = 10m

h = 6.6261 × 10^-34 Js

c = 299792458 m/s

Step 3:

E = (6.6261 × 10^-34)(299792458)/ 10

Step 4:

E = 1.9864548^-25/ 10

E = 1.9864548^-26 J (Joules)

You can use this free online energy of a photon calculator to verify the example in a fraction of time.

How to Use this Online Calculator:

The free online photon energy calculator determines the photon energy results in a fraction of seconds. Just stick to the following points for the accurate outcomes.

Swipe on!


  • Only you have to enter the wavelength of the photon in the designated field of the tool.
  • Then, hit the calculate button.


Once you enter the wavelength, the online calculator shows:

  • Photon energy in:
    1. Joules.
    2. Electron Volt (eV).
    3. Kilo Electron Volt (keV).
    4. Mega Electron Volt (MeV).
    5. Micro Electron Volt (μeV).
    6. Milli Electron Volt (meV).
    7. Nano Electron Volt (neV).
  • Frequency in Hertz (Hz).

The energy of a photon is a smaller quantity as the Planck’s constant has a small number. So, this online energy of a photon calculator to determine the results in different smallest units. Also, to further explore the relationship between frequency & wavelength you can use this online calculator.

Frequently Ask Questions (FAQ’s):

How much energy is in a photon?

The energy of a single photon can be determined by E = hv; where h is Planck’s constant and v is velocity. The energy of a photon is approximately equal to the 10-19 joules.

What happens when the energy of a photon increases?

As the energy is directly related to the frequency, if the energy increases, the frequency also goes upward and wavelength decreases. Because the energy is inversely related with the wavelength. In simple words, the photon can be described by its frequency, wavelength or energy. For determining wavelength to energy relation, use our photon energy calculator that exactly tells you the relationship between the two quantities with each other.

How many moles are in a photon?

To determine the answer, use the following formula:

E = Nhc / ƛ


N is Avogadro’s number (6.02 x 10^23).

h is Planck’s constant.

c is the speed of light.

ƛ is the wavelength.

What happens to the energy of a photon if the wavelength is doubled?

According to Einstein’s Quantum theory of light, the energy of a photon is the product of Planck’s constant and frequency, so, if we double the wavelength, then the energy becomes half.

Final Words:

Thankfully, you come to know about the photon energy and how to calculate it. For easiness, try an online energy of a photon calculator that helps you to figure out the energy of a single photon by considering its wavelength. When it comes to manual calculations, use the above discussed formula for the accurate results.


From the authorized source of Wikipedia : General information and definition with example.

From the site of sciencedirect.com : Overview of Planck’s equation.

From the source of britannica.com : Modified form of Planck’s constant.