Hi Alison, you just divide the square feet into the rent :) so if rent was $1000 per month and square footage was 500, then he rent would be $2.00 per square foot. Did I understand your question correctly? Call me anytime at 415 860 73845.
In residential rentals the price per square foot isn't really a comparable stat. It is used in commercial rental and leasing much more.
Any price per square foot is just the simple equation of dollars paid or requested divided by the stated area (SF).