Usable square feet (USF) is the area inside a commercial suite that a tenant occupies and controls exclusively, including private offices, workstations, conference rooms, and internal storage. It excludes shared building elements like public corridors, lobbies, and mechanical rooms. USF is the space a tenant can actually furnish and use.
How Is Usable Square Feet Measured?
Usable square feet is measured as the floor area a tenant occupies exclusively, bounded by the finished surfaces that enclose the suite. Per the BOMA standard, usable area is measured from the tenant side of common corridor walls, the inside surface of exterior building walls, and the centerline of partitions that separate the tenant from adjacent suites.
Structural columns and projections inside the suite are counted in usable area rather than deducted, so the tenant is not credited for space a column occupies. What is excluded is space serving the whole building: public corridors, elevator shafts, stairwells, shared restrooms, and mechanical and electrical rooms. Those excluded areas reappear in rentable square feet through the load factor.
Element | Counted in USF? |
Private offices and workstations | Yes |
Conference rooms and internal storage | Yes |
Structural columns inside the suite | Yes, not deducted |
Public corridors and lobbies | No |
Shared restrooms, elevator shafts, mechanical rooms | No |
Floor type changes the count. Per the Coy Davidson tenant advisory guidance, a full-floor tenant's usable area includes everything inside the glass line, restrooms and mechanical rooms included, while a partial-floor tenant's usable area stops at the suite and shared corridors are allocated separately as common area.
Why Usable Square Feet Matters
Usable square feet matters because it is the only number that reflects how much space a tenant can put people and furniture in, yet rent is charged on the larger rentable figure. Space planners use USF, not rentable square feet, to test whether a floor plate fits the required headcount and layout before a lease is signed.
Per commercialrealestate.loans, usable area is of prime interest to a tenant in evaluating space and allocating room for personnel and furniture. A tenant that plans against rentable square feet will overestimate capacity, because a slice of that rentable total, often 10% to 20% and higher in dense markets, is common area it cannot occupy. Comparing two suites on usable square feet, not rentable, is the only apples-to-apples test of fit.
The quotable point for a space planner: usable square feet is what you build out, rentable square feet is what you pay for, and only the first tells you if your team fits.
Example
A tenant is comparing two suites, each quoted at 10,000 rentable square feet. Suite A sits on a multi-tenant floor with a 1.18 load factor. Suite B is a full floor with a 1.08 load factor. Usable square feet equals rentable square feet divided by the load factor.
Suite | Rentable SF | Load factor | Usable SF (RSF / load factor) |
Suite A (multi-tenant) | 10,000 | 1.18 | 8,475 |
Suite B (full floor) | 10,000 | 1.08 | 9,259 |
Both suites cost the same rent, but Suite B delivers 9,259 usable square feet versus 8,475 in Suite A, a difference of 784 square feet the tenant can furnish. On identical rentable footage, Suite B is roughly 9% more usable space for the same rent.
Variations and Edge Cases
Usable square feet varies with measurement standard and floor configuration, so identical suites can report different usable totals. Whether columns are deducted, how full-floor common areas are treated, and which standard governs all shift the number. The table below separates the variants an operator should confirm before space planning.
Variant | Treatment |
Full-floor tenant | Usable area includes in-suite restrooms and mechanical rooms inside the glass line |
Partial-floor tenant | Usable area stops at the suite; shared corridors allocated as common area |
Column treatment | Structural columns counted in usable area, not deducted, under BOMA |
BOMA vs REBNY | Different boundary rules produce different usable and rentable figures |
Circulation within suite | Internal corridors serving only the tenant remain usable, not common |
The common mistake is space planning against rentable square feet. Only usable square feet reflects the area a tenant can occupy, and it is the correct basis for a fit test.
Usable Square Feet vs Rentable Square Feet
Usable square feet is often confused with rentable square feet, and the two describe different things the tenant is measured against. Usable square feet is the area a tenant occupies exclusively inside its suite. Rentable square feet is that usable area plus a pro rata share of building common areas. Rentable square feet is what the tenant pays on.
The gap is the load factor. A 10,000 usable-foot suite in a building with a 15% load factor is 11,500 rentable square feet. The tenant furnishes 10,000 but pays on 11,500. Usable square feet answers "will my team fit," while rentable square feet answers "what is my rent."
Frequently Asked Questions
What does usable square feet include?Usable square feet includes the area a tenant occupies exclusively, such as private offices, workstations, conference rooms, and internal storage. It counts structural columns inside the suite but excludes shared building elements like public corridors, lobbies, shared restrooms, and mechanical rooms.
How do you calculate usable square feet from rentable square feet?Usable square feet equals rentable square feet divided by the load factor. For example, a 10,000 rentable-square-foot suite with a 1.18 load factor has 8,475 usable square feet. The result is the space a tenant can actually furnish and occupy.
Is usable square feet or rentable square feet used for space planning?Usable square feet is used for space planning because it reflects the area a tenant can occupy with people and furniture. Rentable square feet includes common areas the tenant cannot use, so planning against it overstates capacity.
Related Terms
Rentable Square Feet
Loss Factor
Tenant Improvement Allowance
Market Rent
Price Per Square Foot