Glossary / Space and measurement
Also known as: USF, usable area, usable square footage
The floor area a tenant actually occupies and controls inside its premises, excluding shared building areas like lobbies, restrooms, elevators, and common corridors. Usable area is the starting point for calculating rentable area.
Schorr Law defines usable square feet as "the actual space contained within the walls of the leased premises," excluding common facilities like lobbies, restrooms, stairwells, elevators, and shared hallways. Moorhead Law Group describes it as the space over which the tenant has exclusive control and possession.
Usable area is converted to Rentable square feet (RSF) by applying the building's Load factor. Tyler Cauble notes that in multi-tenant office buildings a tenant's usable space may be 12 to 18 percent smaller than its rentable space.
Tenants plan around usable space, but landlords charge on rentable space. If your commission is a share of rent, the fee follows rentable area, so two spaces with the same usable area can produce different rent and different commissions depending on each building's load factor.
For tenant rep brokers, comparing options on cost per usable square foot shows the client what it is really paying for. For landlord rep brokers, knowing the usable figure helps you answer tenant questions before they slow a deal down.
Ask for both usable and rentable figures on every space so you and your client compare buildings on the same basis.
For example, a hypothetical tenant needs 8,000 usable square feet. Building A has a 1.10 load factor, so the space is 8,800 RSF. Building B has a 1.20 load factor, so it is 9,600 RSF. At the same hypothetical $35 per RSF per year, Building A rent is $308,000 a year and Building B rent is $336,000 a year, for the same usable space.
