Usable Vs. Rentable Square Feet in an Office Space

Definition: Usable Square Feet (USF) – The area contained within the demising walls of the tenant space, i.e., the space you occupy.

Definition: Rentable Square Feet (RSF) – Equals the usable square footage plus the tenant’s pro-rata share of the Building Common Areas, such as the lobby, public corridors, and restrooms.

Rent is quoted in terms of rentable, not usable square footage. The rentable area of virtually every office unit includes a portion of square footage that is used a part of the common area of the office building, for which the tenant is charged rent.
The percentage difference between the rentable and usable area is known as the Add On Factor (it has other names, too). There are exact standards for determining the add on factor in office buildings. It is expressed as a percentage, which can then be applied to the usable square footage to determine the rentable square footage upon which the tenant will pay rent.

Content is provided by SwiftLease leasing agents.

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