Gross vs. Net Square Feet

 
 
 
 
 

What is Gross Square Feet?

Gross Square Feet (GSF) is the total amount of square footage of a building. This includes all spaces within the outside faces of the exterior walls. Examples included in this measurement are common areas, maintenance and operation areas, balconies, attics, walkways, corridors, and any other parts of a building that are accessible within a building. This means that GSF does not include parking lots and other open areas like pools and unexcavated basements. Some construction budgets have costs that are estimated based on the gross square feet of the building. In the Top Shelf Model’s templates, the construction budgets therefore have the option for both hard and soft cost line items to be based on gross square footage

Gross vs. Net Square Footage

Net Square Feet (NSF) is another popular metric in measuring real estate properties. NSF is defined by the accessible space of a building and includes most space within the inside finished surface walls of a building. Calculating the NSF is more difficult to calculate than GSF, but it is valuable for tenants to know how much space is available for their use. Net Square Feet is made up of Assignable Square Feet and Non-Assignable Square Feet.

 

The Differences between GSF, ASF, Non ASF, SSF

Assignable Square Feet (ASF) is the area of all space of a building that is assigned or available to be assigned to an occupant or specific use. This metric is often times used in universities. The ASF must follow into the following 10 categories for use: classrooms, labs, offices, study facilities, special use, general use, support, health care, residential, and unclassified—that are used to accomplish the institution’s mission. Items that don’t fall into ASF are considered Non-Assignable Square Feet. 

Non-Assignable Square Feet (Non-ASF) is the square footage that is not able to be assigned or available to be assigned to an occupant or specific use. This includes spaces considered as custodial, mechanical, circulation, and public toilet. These items are necessary for operation of the building but just not assignable. 

Structural Square Feet (SSF) is the area of a building that is deemed unusable or unoccupied due to structural building features. Examples of these areas include exterior walls, fire walls, and comparable portions of a building with ceiling height restrictions. Structural Area can be calculated by taking Gross Square Feet (GSF) minus Assignable Square Feet (ASF) and Non-Assignable Square Feet (Non-ASF). 

 

Formulas: 

·       Net Square Feet = Assignable Square Feet + Non-Assignable Square Feet

·       Structural Square Feet = Gross Square Feet - Assignable Square Feet – Non-Assignable Square Feet

 

About the Author

Brittany Martin is TSM’s Vice President who has developed real estate financial models for an extensive range of property types. She specializes in hotel, land, and storage models. Please reach out to her if you have any questions about Gross Square Feet (GSF) or if she can help you with your modeling needs

 
Brittany Martin