The direct answer
For an annual per-square-foot rent quote, multiply rentable area by the annual rate. Add separately modeled pass-through rates on the same area basis, then divide the annual total by 12 for a monthly planning average.
Confirm the quote’s units
An annual $30 per-square-foot quote is different from a monthly $30 per-square-foot quote. Also confirm that the area is rentable area, not another building measurement. A load factor or shared-area treatment can change billable space, but the calculator does not infer it from usable area. Use the area and period defined by the lease or quote.
To apply the approach to an editable scenario, use the Commercial Rent Calculator. For the neighboring question, explore NNN Lease Calculator.
Separate base rent from occupancy charges
CAM, taxes, insurance and other pass-through amounts can be stated as annual rates per square foot. The model multiplies each by the same entered area. Actual agreements can have different allocation bases, caps or reconciliation mechanisms. Do not assume that all pass-through costs are fixed for the full lease term just because the initial scenario uses one rate.
Interpret monthly cost as an average
The monthly output is annual total divided by 12. It does not reproduce actual invoices or a year-end reconciliation. Utilities, fit-out and other unentered costs can remain outside the total. When comparing quotes, use the same service scope and area convention so a lower base rate does not hide larger additional charges.
Worked example
For 5,000 rentable square feet at $30 annual base rate, base rent is $150,000. Additional rates totaling $15 per square foot add $75,000. Total annual modeled occupancy cost is $225,000, with an $18,750 monthly average.
Common mistakes and limitations
Do not multiply an annual per-square-foot rate by 12 again. Do not compare rentable area with another quote’s usable area without reconciling the difference.
Lease definitions of rentable area, CAM, exclusions, caps and reconciliations vary by contract.
Frequently asked questions
Are utilities automatically included?
No. Only the entered cost components are included in the modeled total.
Does the monthly amount equal a contractual invoice?
It is an annual total divided by 12; the actual payment schedule and reconciliations can differ.
Sources and further reading
The article’s examples are illustrative arithmetic. The references below provide context for operating, valuation or transaction concepts; they do not endorse the assumptions or the calculator.
- Office of the Comptroller of the Currency — Comptroller's Handbook — Commercial Real Estate LendingNOI, direct capitalization, cap-rate valuation and DCF concepts for commercial real estate.
Read our editorial policy for the scope of these educational methods.