This was too useful not to share:

https://www.rpglibrary.org/utils/meddemog/

If you're setting up a fictional kingdom, this was very useful in breaking down populations for a medieval type setting. Obviously, you can fudge numbers, but it's a great way to let someone else do the majority of the brainwork and tweak it to suit your needs. My kingdom is relatively small and initially I had more towns and a larger military than the place could properly support.

I only started the math because I was trying to rank certain members of a nobility class based on their wealth (which will more or less correlate to their population, # of villages, etc.). I certainly didn't need to math THAT much today.