Glossary

Load Factor

Also known as: R/U ratio, rentable-to-usable ratio

The ratio of Rentable Square Feet (RSF) to Usable Square Feet (USF) for a given floor or suite, expressing how much common-area space is added on top of a tenant's exclusive-use area for rent-paying purposes.

Load factor is calculated as RSF divided by USF and is typically expressed as a percentage or decimal multiplier (e.g., a 1.15 load factor means a tenant pays rent on 15% more area than it can physically occupy). It is one of the first figures a tenant's broker checks when comparing buildings, because two spaces with identical quoted rental rates and identical usable area can have materially different effective costs if their load factors differ: a building quoting $60/RSF with a 1.20 load factor is more expensive per usable foot than one quoting $62/RSF with a 1.10 load factor. Load factors vary by building type and vintage — full-floor leases in efficient modern towers often run 1.08 to 1.15, while multi-tenant floors in older buildings with generous common corridors, multiple elevator lobbies, or inefficient cores can run 1.20 to 1.35 or higher. Sophisticated tenants negotiate a load factor cap or a "not-to-exceed" ceiling in the lease, tied to a specific measurement standard, precisely because landlords retain discretion in how common areas are allocated and re-measured over the lease term.