Load Factor Calculator

The load factor (also called the core factor or add-on factor) represents the ratio of rentable area to usable area in a building. It reflects how much common area (lobbies, corridors, restrooms, mechanical rooms) you pay for in addition to your exclusive space.

Load factors typically range from 1.10 to 1.20 (10% to 20% common area add-on) for multi-tenant office buildings. Factors above 1.20 should be scrutinized. Single-story retail properties often have lower load factors near 1.05.

No, the rentable and usable square footage should be fixed in your lease. If a landlord remeasures the building using a newer BOMA standard and applies it to your existing lease, that likely violates your lease terms unless your lease explicitly permits remeasurement.

A load factor above 1.20 warrants a formal verification request. Ask your landlord for the BOMA measurement methodology and supporting floor plan documentation. If the load factor increased since you signed your lease, compare it to the rentable square footage stated in your original lease. CAMAudit's Pro-Rata Share Error rule analyzes your actual lease and reconciliation to detect whether an inflated load factor is causing you to overpay your share of the expense pool.