Usable Square Footage or USF is the total usable floor area of a space or building. It is measured from the outside or outer surface of any exterior walls and windows, including the middle of any interior walls that are adjacent to other spaces, hallways or common areas. Similar to how homes are assessed, the measurements are from the outside of the exterior walls, not by measuring from the inside of the walls.

Usable Square Footage is the space the tenant will actually occupy, as compared to the Rentable Square Footage the tenant will pay rent on. (See Rentable Square Footage also).

Usable Square Footage can sometimes also be called Leasable Square Footage or USF.

Architects and Tenants will often measure a space from the inside of all walls of the space and in doing so, will calculate a total square footage that is lower than the landlord’s calculation of the Leasable or Usable Square Footage. It’s important to understand the location of the measurements as well as even the thickness of the walls. When measuring a space, an architect or space planner can help ensure a more accurate measurement. Additionally, comparing in-person or field measurements to a verified CAD document can also decrease the margin of error.

Usable Square Footage should not include any common areas of the building such as public corridors, hallways, common areas, restrooms, etc.