business model: considering cost of running a business?

In the money per year section are we considering revenue or profit?
I own a medical spa. So how do I consider things like rent or paying employees into each botox injection? Obviously the profit will be more or less depending on how many I sell. So if I sell one patient per day I have to consider that whole days pay to employees and rent where as if I sell 20 that day it will be a 20th. This dramatically effects how much I make. Thanks for any help you can offer!