When seeking office space for lease or purchase, it is important to understand exactly how much space you are looking at acquiring. Many prospective office tenants and buyers do not understand the major difference between rentable and usable square feet and how this will affect their rental or purchase expense.
It can be very confusing trying to find office space on your own when square footage can be shown in several different ways. Sometimes the size is just advertised as square feet or “SF”. The numbers that you really need to see and understand are what is the rentable square feet (RSF) and what is the usable square feet (USF) of the space.
The difference between rentable and usable square feet can be simplified as follows:
- Rentable Square Feet (RSF) is the total square footage that you will have to pay rent on. In many single-story buildings that have no shared common area, the rentable square feet is the same as the usable square feet. The rentable square feet includes the amount of space within the walls of your suite, but also your proportionate share of the building common areas. The common areas may include hallways, restrooms, stairwells, elevator shafts, building mechanical rooms, and sometimes even parking garages. Depending on how efficient the building is, the rentable square feet can add on a lot of size to your space.
- Usable Square Feet (USF) is the total square footage that is within the walls of your suite. If you are in a single-tenant building or if your multi-tenant building has no common areas, then this number will be the same as your rentable square feet. The amount of space that you pay rent on is not determined by the usable square feet, but your employee density is. Your landlord and local ordinance codes will use this number to determine how many people can occupy the space at a single time.
An example of the difference between rentable and usable square feet can be seen in the image below:
In this theoretical space plan, you are looking to lease the available space shown. The usable square feet is 5,400 sf (60′ x 90′). The rentable square feet is the usable plus your proportionate share of the building common areas. If each of the 4 spaces are all exactly 5,400 USF and the building’s total size is 27,300sf (130′ x 210′), then the total common area size is 5,700 sf (27,300 – 21,600)…(the 21,600 comes from 5,400 x 4 spaces). 5,700 sf / 4 = 1,425 sf, thus making 1,425 sf the add on factor. This then makes your 5,400 USF space into a 6,825 RSF space.
Unless you are a commercial real estate professional, it is in you best interest to have a knowledgeable Tenant Representative help you with your office space search and negotiations. A Tenant Representative not only saves you time and money during the office leasing process, but they also grant the satisfaction of knowing that you avoided potentially costly mistakes when negotiating on the fine print lease terms.