Commercial Lease Space Cost Calculator
Calculate the total cost of leasing commercial space including base rent, NNN charges, operating expenses, and one-time fees.
Formulas Used
Monthly Base Rent (Year 1):
Monthly Base Rent = (Base Rent Rate × Sq Ft) ÷ 12
Annual Escalation (compounding):
Monthly Base Rentyear y = Monthly Base Rentyear 1 × (1 + Escalation Rate)y
NNN Monthly Charge:
NNN Monthly = (Property Taxes + Insurance + CAM) × Sq Ft ÷ 12
Total Occupancy Cost:
Total = Σ (Monthly Base Rent + NNN Monthly + Parking) for each paying month
(Free rent months are excluded from base rent and NNN payments)
Net Effective Total Cost:
Net Effective Cost = Total Occupancy Cost − TI Allowance
Effective Annual Cost per Sq Ft:
= Net Effective Total Cost ÷ (Lease Term in Years) ÷ Sq Ft
Security Deposit:
Security Deposit = Security Deposit Months × Year-1 Monthly Base Rent
Assumptions & References
- Base rent rates are quoted as annual dollars per rentable square foot ($/SF/yr), the standard U.S. commercial leasing convention (BOMA International).
- Gross Lease: Tenant pays a flat rent; landlord covers taxes, insurance, and maintenance.
- Triple Net (NNN) Lease: Tenant pays base rent plus their pro-rata share of property taxes, building insurance, and common area maintenance (CAM). NNN charges are held constant over the term as an approximation; actual charges float annually.
- Modified Gross Lease: A hybrid where the tenant pays base rent plus specified operating expenses negotiated at signing.
- Annual rent escalation is applied on a compounding basis at each lease anniversary (year boundary), consistent with standard CPI or fixed-step escalation clauses.
- Free rent (abatement) periods are applied to the beginning of the lease; no base rent or NNN is charged during this period.
- Tenant Improvement (TI) allowance is a landlord-funded credit toward build-out costs and is subtracted from total occupancy cost to derive the net effective cost.
- Security deposit is treated as a refundable upfront cost and is not included in the net effective total cost.
- Parking costs are assumed fixed monthly and are not subject to escalation.
- This calculator does not account for percentage rent clauses, gross sales overages, or utility costs beyond CAM.
- References: BOMA International Lease Guide; CoStar Group commercial lease benchmarks; CCIM Institute lease analysis methodology.