Commercial Square Footage: GLA, Rentable, and Usable
Commercial space is measured four ways: gross leasable area (GLA) for retail tenants, rentable square feet (RSF) and usable square feet (USF) for offices, and gross area for the whole building. Rentable is usable plus a share of the common areas, so the same suite carries two numbers. Always ask which one a listing or lease quotes.
The four commercial measures
A listing can quote any of them, and for an office suite rentable is always the largest figure.
The whole building, every floor, to the outside faces of the exterior walls, shafts and stairs included (KU space glossary). For zoning, see gross floor area.
Retail tenant space; see below.
Usable space plus a share of the lobby, corridors and restrooms. A rate quoted per RSF bills the larger number.
The space you occupy and can lay out. GSA leases call it ANSI/BOMA office area.
How to calculate rentable square feet
Multiply the usable area by 1 plus the load factor, which GSA leases call the common area factor.
Rentable sq ft = usable sq ft × (1 + load factor)
The load factor is common area divided by usable area. Here's what it does to rent on two offices with the same 1,000 usable sq ft, both quoted at $28 per sq ft per year:
1,120 RSF, or $2,613 a month.
1,200 RSF, or $2,800 a month.
Same rate, same working space, $2,240 a year apart. Compare offers on the usable figure, and check whether a rate is yearly or monthly: $28 a year is $2.33 a month per sq ft. The price per square foot calculator runs the rent math.
Gross leasable area in retail
Gross leasable area is the total area rented to tenants, including basements and mezzanines, measured from the outside of the exterior walls to the centerline of the walls between tenants (INREV). Space no tenant rents, such as mall corridors, isn't in it. In home listings GLA means something else: residential gross living area, the finished, above-grade space an appraiser measures in a house.
Gross floor area counts the whole building for zoning; GLA counts only the tenant spaces inside it.
GLA leaves common areas out; office rentable area adds a share of them in.
Because GLA runs to the outside of the exterior walls, it's larger than what you'd measure inside the unit. Gross vs net square footage shows by how much.
Which standard applies
Each property type has its own BOMA measurement standard; these are the current editions on BOMA's standards list.
Ask for usable area and the load factor. Conference room size shows how much space meeting rooms take.
Quoted in gross leasable area.
Warehouses and industrial buildings.
Measuring a commercial building
For a simple building, square footage is still length times width for each floor, added together.
- Measure the footprint to the outside of the exterior walls.
- Measure each floor separately, mezzanines included, and add them.
- Don't deduct columns or partitions from a gross figure.
- Split shared walls down the middle between tenants in a multi-tenant building.
The square footage chart lists more sizes, and the rectangle calculator adds the perimeter for fencing and exterior wall estimates.
Frequently asked questions
What is gross leasable area?
It's the total floor area rented to tenants, including basements and mezzanines, measured from the outside of the exterior walls to the centerline of walls shared with other tenants. Shopping centers report their size in GLA.
What does RSF mean in real estate?
RSF means rentable square feet: the space a tenant occupies plus its share of common areas such as the lobby, corridors and restrooms.
How do you calculate rentable square footage?
Multiply usable square feet by 1 plus the load factor. A 2,000 sq ft suite with a 15% load factor is 2,000 × 1.15, or 2,300 rentable sq ft.
What is usable square footage?
It's the floor area inside a tenant's own space, the part you can furnish, before any share of the building's common areas is added.
What is the difference between GLA and GFA?
Gross floor area is the whole building, every story, used for zoning and floor area ratio. Gross leasable area is only the part rented to tenants, so it's smaller.
What is the difference between NSF and GSF?
GSF (gross square feet) is all floor area inside the outside faces of the exterior walls, stairs and shafts included. NSF, or net assignable square feet, counts only space assigned to an occupant or use, so it's smaller.