Lease Cost Comparator (NNN vs Gross)
Compute the true all-in occupancy cost of a Triple Net (NNN) lease versus a Gross lease over your full lease term, including base rent escalations, NNN expense pass-throughs, tenant improvement allowances, and free rent periods. Enter the terms of both lease options to see the numbers before you sign. Everything runs in your browser with no data stored or transmitted.
Lease A (NNN)
Lease B (Gross)
NNN total occupancy
$247,408
Gross total occupancy
$282,645
NNN avg monthly
$4,123
Gross avg monthly
$4,711
NNN effective $/sqft/yr
$24.74
Gross effective $/sqft/yr
$28.26
Year-by-year comparison
| Year | NNN | Gross | Difference |
|---|---|---|---|
| 1 | $43,333 | $51,333 | -$8,000 |
| 2 | $53,560 | $57,680 | -$4,120 |
| 3 | $55,167 | $59,410 | -$4,244 |
| 4 | $56,822 | $61,193 | -$4,371 |
| 5 | $58,526 | $63,028 | -$4,502 |
In a triple net (NNN) lease you pay base rent plus your share of property taxes, insurance, and common area maintenance (CAM). Those pass-through costs can rise even when base rent is flat.
This is a financial comparison tool, not legal advice. Have your lease reviewed by a commercial real estate attorney.
How this tool works
For each lease, the calculator computes base rent per year (base rate per sqft times footage, compounded by the annual escalation), adds NNN expense pass-throughs for NNN leases, and zeros out any months within the free rent period. Tenant improvement allowances are subtracted from the total at the end. The result is a side-by-side total occupancy cost, a year-by-year cost table, and the average monthly and effective per-sqft rate for each option.
Worked example
2,000 sqft, 5-year term. NNN: $18/sqft base plus $8/sqft NNN, 3% escalation, 2 months free rent, $20,000 TI. Gross: $28/sqft all-in, 3% escalation, 1 month free rent, $10,000 TI. After netting TI and free rent, total 5-year NNN cost is approximately $222,000 and gross approximately $240,000, making NNN the winner in this scenario. The year-by-year table shows when costs cross if NNN pass-throughs spike beyond the 3% escalation assumption.
Frequently asked questions
What is a Triple Net (NNN) lease?
In a Triple Net lease, the tenant pays base rent plus a proportionate share of three property expenses: property taxes, building insurance, and common area maintenance (CAM). Base rent appears lower than a gross lease, but the total cost is often similar because the NNN expenses add to the monthly bill.
What is a Gross lease?
A Gross lease bundles property taxes, insurance, and maintenance into the base rent. The tenant pays one fixed amount per month and the landlord handles the variable operating costs. Gross leases offer cost predictability; the risk of expense increases falls on the landlord rather than the tenant.
Which lease type is better for tenants?
A Gross lease offers predictability: your monthly payment does not change when the landlord gets a tax reassessment or replaces the roof. An NNN lease can cost less if the landlord's actual expenses are lower than the gross lease premium, but expense spikes create surprise bills. This calculator lets you compare based on your specific quote.
What is a tenant improvement allowance?
The landlord's contribution toward your build-out costs. A $20,000 TI allowance means the landlord pays $20,000 toward walls, flooring, fixtures, or other improvements. A higher TI effectively reduces your net occupancy cost but may be reflected in higher base rent. This calculator subtracts TI from total cost for an accurate comparison.
What does free rent mean in a lease?
Free rent (also called rent abatement) means you pay no base rent for a specified number of months at the start of the lease, typically 1-3 months. It is used as an incentive to sign. Free rent reduces your total cost but may not apply to NNN expenses or operating costs during that period.
What are CAM charges in an NNN lease?
Common Area Maintenance charges cover the cost of maintaining shared areas: parking lots, lobbies, landscaping, elevators, and hallways. CAM charges can vary year to year. Some leases cap annual CAM increases; always negotiate a CAM cap before signing an NNN lease to limit exposure to sudden expense increases.
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