Glossary / Space and measurement
Also known as: RSF, rentable area, rentable square footage
The area a tenant pays rent on: its usable square feet plus a proportional share of the building's common areas such as lobbies, corridors, and restrooms. Office rent is usually quoted per rentable square foot.
Schorr Law defines rentable square footage as "the usable square footage plus a portion of the building's common area or shared space." The ANSI blog on the BOMA office standard describes rentable area the same way: the space a tenant uses plus a share of shared spaces like lobbies, hallways, and restrooms.
Rent is calculated on rentable, not usable, area. Moorhead Law Group gives the formula as usable area times Load factor equals rentable area, then rentable area times the dollar-per-square-foot rate equals annual base rent.
When a commission is calculated as a share of rent over the lease term, RSF is a direct input: more rentable feet at the same rate means more rent, and a larger fee base. A remeasurement or a different measurement standard can change the RSF in the lease, so confirm the figure in the final lease matches the figure you used to estimate your fee.
RSF is also what your client compares when touring. A space with a lower rate per RSF can still cost more if the building has a higher load factor, so tenant rep brokers should compare deals on both usable and rentable area.
Always confirm the RSF in the final lease, since it drives both the rent and any commission calculated on that rent.
For example, a hypothetical tenant needs 5,000 usable square feet in a building with a 1.15 load factor. That is 5,750 RSF. At a hypothetical $40 per RSF per year, annual base rent is $230,000, and a 5-year term with no escalations produces $1,150,000 in base rent.
