CAM Charge Calculator
Split common area maintenance costs by pro-rata share of square footage, add the admin fee, and get a tenant’s annual, monthly and per-sq-ft CAM.
How it works
Pro-rata share = tenant sq ft ÷ total sq ft · CAM = budget × share × (1 + admin%)
Common area maintenance charges pass a building’s shared costs — landscaping, parking, security, lighting and common-area repairs — through to tenants in proportion to the space they lease. A tenant’s pro-rata share is their square footage divided by the leasable total, and a management admin fee is usually layered on top of the base. Because CAM is billed on top of base rent, the per-square-foot CAM is a real part of occupancy cost that tenants should compare across buildings.
Worked example
A tenant with 2,500 of 40,000 leasable sq ft has a 6.25% share. On a $120,000 CAM budget that is $7,500 of base CAM; a 15% admin fee adds $1,125 for $8,625 a year — $718.75 a month, or $3.45 per sq ft.
Frequently asked questions
How is a tenant’s CAM share calculated?
Divide the tenant’s leased square footage by the property’s total leasable square footage to get the pro-rata share, then apply that percentage to the CAM budget. Some leases use gross leasable area including vacant space, others only occupied space — check which your lease specifies.
What is the admin fee on CAM?
It is a management markup on the base CAM, commonly 10–15%, meant to cover the cost of administering the shared services. It applies on top of the actual expenses, so it raises the tenant’s effective CAM rate.
What is the difference between a CAM cap and a base year?
A CAM cap limits how much the controllable portion of CAM can rise year to year, protecting the tenant from spikes. A base-year (or expense stop) structure instead bills only CAM above a first-year baseline. Both are negotiated to bound the tenant’s exposure.
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Educational estimate, not financial or investment advice.