Photon Energy Calculator

Calculate photon energy from wavelength or frequency using the Planck relation.

About Photon Energy Calculator

Photon energy is inversely proportional to wavelength, so blue light carries more energy per photon than red. Visible photons are around 2 to 3 electronvolts, which is why that range drives photochemistry. The electronvolt is the natural unit here because it matches the scale of atomic and molecular energy levels.

Formula

Photon Energy

E = h f = h c ÷ λ

h: Planck constant, 6.626 × 10⁻³⁴ J·s
c: Speed of light in vacuum

Worked example

With the default values below, Photon Energy Calculator returns Photon Energy of 0.0000000000000000003612. Change any input above and every figure here is recalculated in your browser.

Inputs used

Wavelengthminimum 0.001 nm: 550 nm

Results

Photon Energy: 0.0000000000000000003612 J
Photon Energy: 2.25426 eV
Frequency: 545,077,196,363,636 Hz
Photons per Joule: 2,768,764,112,148,490,000
Spectral Region: Visible light

Step by step

1Values used
2Photon Energy
3Photon Energy= 0.0000000000000000003612 J
4Photon Energy= 2.25426 eV
5Frequency= 545,077,196,363,636 Hz
6Photons per Joule= 2,768,764,112,148,490,000
7Spectral Region= Visible light

Assumptions and limits

The result is derived only from the single input listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 22 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Photon Energy calculated?

E = h f = h c ÷ λ Photon energy is inversely proportional to wavelength, so blue light carries more energy per photon than red. Visible photons are around 2 to 3 electronvolts, which is why that range drives photochemistry.

Why does Photon Energy matter?

The electronvolt is the natural unit here because it matches the scale of atomic and molecular energy levels.

What values do I need to enter?

This calculator takes 1 input: Wavelength. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.