Why do I pay rent on more square footage than I actually use?
Commercial rent is calculated on rentable square footage, not the usable space you actually occupy.
Rentable square footage adds a proportional share of the building's common areas — lobbies, corridors, shared restrooms — to your usable area. The percentage added is called the load factor, and it typically ranges from about 10% to 20%. This means a 2,000 usable square foot suite might be billed as 2,300 rentable square feet. Because two buildings can quote the same per-square-foot rate but carry very different load factors, comparing rents without knowing each one is misleading — a lower rate on a higher load factor can cost more overall. Always ask for both the usable and rentable figures, and the load factor between them, before comparing spaces.
Related FAQ terms
Have more questions?

- Tenant & owner occupied representation
- Healthcare & service-focused
- Chicago & suburban markets