Example: 2.4e9 for 2.4 GHz.
Frequency in Hz and speed of light c = 299 792 458 m/s—wavelength in meters (vacuum / ideal).
Example: 2.4e9 for 2.4 GHz.
In vacuum, λ = c ÷ f with c = 299 792 458 m/s (exact SI definition) and frequency f in hertz. The page shows wavelength in meters and nanometers; it does not model propagation in a medium (refractive index).
This calculator uses plain decimal numbers. If a result looks wrong, check whether you used a comma instead of a dot (or vice versa) where the field expects one.