Useable Square Feet:
The space you have for your exclusive use. Useable SF is measured starting midway between the wall of your rental unit and that of the neighboring rental unit. Also, the tenant’s Useable SF usually includes some or all the space between the interior wall and the outside of the building.
The part of the building used by more than one tenant e.g. the mailroom, maintenance closets, and bathrooms
Also called common area factor or add-on factor, represents the proportional amount of common area allocated to each tenant. Each building has a different load factor based upon common areas in the building. Load Factor = Building Gross SF/Building Useable SF
Rentable Square Feet:
Includes the Useable SF and the tenant’s share of the building common areas. Base rent usually is paid on Rentable SF, rather than Useable SF. To determine the Rentable SF, the tenant’s Useable SF is multiplied by the load factor.
Gross Square Footage:
The entire square footage of the building from exterior wall to exterior wall.