Photon energy
Fill in any fields — the empty ones are calculated, so it works in every direction.
Formula
E = h·f = h·c / λ
Worked example
Given: Wavelength = 550 nm
Result: Energy = 2.25 eV; Frequency = 545.08 THz
How it is calculated
1. Enter the values you know. 2. The calculator converts them to base units and applies the formula. 3. The result is shown in the unit you choose.
Frequently asked questions
How do I calculate it?
Formula: E = h·f = h·c / λ. Given: Wavelength = 550 nm. Result: Energy = 2.25 eV; Frequency = 545.08 THz.
Is the calculator free and private?
Yes. It is free, needs no sign-up and runs in your browser — the numbers you type stay on your device.