Commercial Lease Calculator

Estimate monthly and annual rent for a commercial space from square footage, rate per square foot, and lease type, plus the total lease cost after annual rent escalation over the full term.

Quick Facts

Formula
Annual Rent = Sq Ft × Rate per Sq Ft (+ NNN charges)
Each later year is escalated: Year N Total = Year 1 Total × (1 + escalation)^(N − 1).
Lease types
Gross, Modified Gross, and Triple Net (NNN)
NNN tenants also pay a share of property taxes, insurance, and common-area maintenance (CAM) on top of base rent.

Your Results

Calculated
Monthly rent (Year 1)
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Base rent + applicable operating expenses
Annual rent (Year 1)
-
First-year total before escalation
Total lease cost (full term)
-
Sum of all years with escalation applied
Effective average rate
-
$/sq ft/year averaged across the term

Ready

Enter square footage, rent rate, lease type, and term, then press Calculate.

How the Commercial Lease Calculator works

Commercial rent is almost always quoted per square foot per year, and the total you owe depends on the lease structure as much as the rate itself. This calculator applies the standard base-rent formula, adds operating expense pass-throughs for net leases, and compounds the result by your negotiated annual escalation to project the full cost of the lease term.

The formula

Annual base rent is Annual Base Rent = Square Footage × Rate per Sq Ft. Net leases add a pass-through for property taxes, insurance, and common-area maintenance (CAM): Year 1 Total = Annual Base Rent + (Square Footage × Operating Expense Rate × Pass-Through Share), where the pass-through share is 0% for a full-service gross lease, about 50% for a modified gross lease, and 100% for a triple net (NNN) lease. Each later year of the term is escalated by the annual increase: Year N Total = Year 1 Total × (1 + escalation)N − 1, and the total lease cost is the sum of that geometric series across the full term.

Worked example

Take 2,500 sq ft at $24/sq ft/year in base rent under a triple net lease, with $8/sq ft/year in operating expenses and 3% annual escalation over a 5-year term. Year 1 total is 2,500 × ($24 + $8) = $80,000, or about $6,666.67 per month. Compounding that by 3% a year for 5 years brings the full lease cost to roughly $424,731 — averaging about $33.98 per square foot per year over the term.

What moves the cost most

  • Lease type: a triple net lease passes 100% of operating expenses to the tenant, while a full-service gross lease bundles them into the quoted rate — the same $24/sq ft can mean very different out-of-pocket totals depending on which pass-throughs apply.
  • Escalation rate: even a modest 3% annual increase compounds meaningfully over a 5-10 year term; a 5% escalation on the same space raises the total lease cost noticeably more than a flat 1%.
  • Term length: longer terms multiply the exposure to escalation, so the effective average rate rises for longer leases even though the Year 1 rate stays the same.

What this calculator does not include

This is a rent-cost projection, not a full occupancy-cost or lease-vs-buy analysis. It does not model free-rent periods, tenant improvement allowances, security deposits, percentage rent (common in retail leases), or year-end CAM reconciliation against actual expenses — all of which can shift the effective cost of a lease. Treat the output as a planning baseline and confirm details against the actual lease document before signing.

Frequently Asked Questions

How is commercial lease rent calculated?
Annual base rent equals rentable square footage multiplied by the quoted rate per square foot. For net leases, a share of operating expenses (property taxes, insurance, and common-area maintenance) is added on top: 100% for a triple net (NNN) lease, roughly 50% for a modified gross lease, and 0% for a full-service gross lease where those costs are already built into the base rate.
What is the difference between gross, modified gross, and triple net (NNN) leases?
In a full-service gross lease, the landlord covers operating expenses out of the quoted base rent. In a triple net (NNN) lease, the tenant pays base rent plus their full share of property taxes, insurance, and CAM charges. A modified gross lease splits the difference, with some expenses built into rent and others billed separately — this calculator models that split as roughly half the quoted operating expense rate.
Why does the total lease cost grow faster than Year 1 rent times the term?
Most commercial leases include an annual rent escalation clause, commonly 2% to 5% per year, that compounds the rent each year of the term. Multiplying Year 1 rent by the number of years ignores that compounding, so the actual total is higher, and the gap grows with both the escalation rate and the length of the term.
Does this include tenant improvements, free rent, or CAM reconciliation?
No. This calculator projects base rent and operating expense pass-throughs only. Concessions such as free-rent periods and tenant improvement allowances, along with year-end CAM reconciliation against actual costs, are negotiated separately and can change the effective cost of a lease — confirm those terms in the lease document itself.

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