Glossary
Lease Terms & Dates
Usable Square Footage
The exact floor area a tenant occupies and controls exclusively, measured before any common-area add-on. Usable square footage is the starting point for calculating rentable square footage and, from there, the tenant's pro-rata share.
Firm impact
A gap between usable and rentable square footage that's larger than typical for the building type points to an inflated load factor, which raises every future CAM bill without changing the space the client actually uses. Firms that check this ratio at intake catch a load-factor problem before it compounds across years of reconciliations.
How this gets abused
A tenant's usable square footage is 6,000 SF, but the lease lists rentable square footage at 7,800 SF, a 30% common-area add-on far above the 10 to 20% range typical for the building type. The inflated load factor pushes the tenant's pro-rata share, and every CAM dollar tied to it, well above what the actual space justifies.
Practitioner note
Request the architect's or surveyor's space measurement certificate and compare it against the usable square footage stated in the lease. If no certificate exists, flag the figure as unverified and request one before accepting the load factor used in the reconciliation.
FAQ
Questions about usable square footage
Why does usable square footage matter if the lease already states rentable square footage?
Rentable square footage is derived from usable square footage plus a load factor. If the usable number was never verified, the rentable number and everything calculated from it, including the tenant's CAM share, rests on an unchecked figure.
Who typically measures usable square footage?
A licensed architect or surveyor measures the space, usually following the BOMA (Building Owners and Managers Association) standard. Your firm should request that measurement documentation, not just the number printed in the lease.
You know the term. Now check the math.
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