The Rubber Ruler The Loss Factor Between Rentable Square Footage and Usable Square Footage

Commercial landlords use “rentable square footage” as the measurement. This measurement includes a proportionate share of common areas in the building, such as corridors, lobbies, rest rooms and elevator vestibules. The “usable square footage” is equal to the measurements of the demised space from the window line to the demising wall. Confused? Basically, usable square footage is always smaller than rentable square footage. The difference between the rentable square footage and usable footage is called the “loss factor” – or as we like to call it, the rubber ruler.

Usable Square Footage

is defined as the square footage that you, the tenant, use exclusively.

Rentable Square Footage

is defined as both the square footage that you use exclusively, as well as the space used by other tenants.

  • In New York City, loss factors are generally between 20% and 40%.
  • Loss factors tend to be greater for space on divided floors and less for full floor spaces.
  • Loss factors tend to be greater in office buildings that are more expensive and exclusive, where historically Tenants have less trouble paying the freight.
  • The higher the loss factor, the more space you need to rent in order to occupy an equal amount of usable space.