Wavelength ↔ frequency

Convert λ ↔ f of EM waves and get the photon energy.

Instant
Free
Private (processed locally)
No sign-up

Convert λ and f

Enter the frequency or the wavelength: the other is computed, along with the photon energy.

Example

Input	Value
Frequency	5×10¹⁴ Hz
Wavelength	≈ 600 nm
Energy	≈ 2.07 eV

c = 299,792,458 m/s. 100% local calculation.

Frequently asked questions

What is the formula?

λ = c / f, with c = 299,792,458 m/s (speed of light in vacuum).

How is energy computed?

E = h·f (h = 6.626×10⁻³⁴ J·s), converted to electronvolts (1 eV = 1.602×10⁻¹⁹ J).

Does it work for sound?

No: here c is the speed of light. For sound the speed depends on the medium (~343 m/s in air).