Radio Frequency Distance

No additional app required.
Use your browser.

https://www.rfwireless-world.com/calculators/rf-wavelength-calculator.html

 

Or a calculator:

Using f = frequency, lambda = wavelength, and c = speed of light (3*10^8 m/s)
c = f*lambda
which gives
lambda = c/f

So divide the speed of light by the frequency and you have the wavelength.

Or if you really just want to sort, higher frequency = shorter wavelength.