A triple net lease, written NNN, is a commercial lease where the tenant pays base rent plus a pro-rata share of the property's three "nets": real estate taxes, building insurance, and common area maintenance (CAM). The landlord collects a rent that is close to net of operating costs, because the tenant reimburses those costs on top. It is the standard structure for single-tenant retail, freestanding stores, and many industrial and shopping-center leases, and it is the reason two tenants paying the same "rent" can owe very different amounts each month.
What NNN means in a lease
The three N's are the three categories of property expense the tenant takes on in addition to base rent:
- Net of real estate taxes: the property taxes assessed by the local jurisdiction, passed through by the tenant's share.
- Net of insurance: the premium for the landlord's property and liability coverage on the building, not the tenant's own business insurance.
- Net of CAM: the tenant's proportionate share of common area maintenance: landscaping, parking lot upkeep, common-area utilities, snow removal, security, and property management fees.
Because the tenant absorbs these variable costs, the quoted base rent on an NNN deal is lower than on a gross lease. That lower headline number is what trips up new tenants: the NNN charges are real money on top, and they move every year.
Who pays for what in a triple net lease
The split is the whole point of the structure. Here is how the common costs land:
| Cost | Who pays in an NNN lease |
|---|---|
| Base rent | Tenant |
| Property taxes | Tenant (pro-rata share) |
| Building insurance | Tenant (pro-rata share) |
| Common area maintenance | Tenant (pro-rata share) |
| Interior repairs and utilities | Tenant |
| Structure, roof, and foundation | Usually landlord (varies by lease) |
| Property management fee | Tenant, if the lease includes it in CAM |
The gray area is almost always the roof and structure. A true "absolute net" or bondable lease pushes even those onto the tenant; a standard NNN keeps them with the landlord. The only way to know which you have is to read the maintenance and repair clause, not the label on the deal sheet.
How triple net charges are calculated
NNN charges are billed as a monthly estimate and then trued up after year-end. The math has two moving parts: the tenant's pro-rata share, and the total pool of recoverable expenses.
Pro-rata share is the tenant's rentable square footage divided by the building's rentable area. So a tenant in 5,000 square feet of a 50,000 square foot center has a 10 percent share.
Say the building's annual NNN pool is: taxes $200,000, insurance $50,000, and CAM $250,000, for a total of $500,000. The 10 percent tenant owes $50,000 a year in NNN charges, billed at roughly $4,167 a month on top of base rent. If base rent is $25 per square foot, that tenant's all-in occupancy cost is $25 plus $10 of NNN, or $35 per square foot, a 40 percent premium over the quoted rate.
Those monthly figures are estimates. After the year closes, the landlord runs a CAM reconciliation comparing estimated to actual expenses and bills or credits the difference. That reconciliation is where overcharges hide, which is why tenants on NNN leases often run a lease audit against the actual clause language.
Triple net vs gross vs modified gross
NNN sits at one end of a spectrum defined by who carries the operating costs. The other end is a gross (or full service) lease, where the landlord pays everything out of a higher rent. In between is the modified gross lease, where the costs are split.
| Lease type | Who pays operating costs | Common in |
|---|---|---|
| Gross / full service | Landlord, from a higher base rent | Office |
| Modified gross | Split; tenant pays some, often increases over a base year | Multi-tenant office |
| Triple net (NNN) | Tenant pays taxes, insurance, and CAM on top of rent | Retail, single-tenant, industrial |
| Absolute net | Tenant pays everything, including structure and roof | Single-tenant credit deals |
When you compare two lease offers, the base rent alone tells you almost nothing. A $30 gross rent and a $22 NNN rent with $10 of nets are not the same deal, and the NNN one is more expensive. Comparing offers means normalizing every one of them to an all-in number, which is exactly the reconciliation an accurate lease abstract supports.
Is a triple net lease good for the tenant or the landlord?
It depends on which side of the table you sit. For landlords, NNN is prized for producing near-passive, predictable income: the tenant absorbs the variable operating costs, so the owner's return is insulated from rising taxes and maintenance. Many single-tenant NNN assets are held precisely for that stability, and the owners of those buildings care mostly about clean year-end numbers and want tidy financial statements for the property without managing day-to-day operations.
For tenants, the appeal is a lower base rent and transparency into what the building actually costs to run, plus, in a well-drafted lease, the right to audit those costs. The risk is exposure: a spike in taxes after a reassessment, or an uncapped CAM pool, flows straight to the tenant. Good tenants negotiate a cap on controllable CAM and a clear list of exclusions, then hold the landlord to both.
What to abstract from a triple net lease
The economics of an NNN lease live in the recovery clauses, not the rent number. When you abstract one, capture:
- Base rent and escalations: the starting rate and its step schedule.
- The pro-rata share and the denominator used to calculate it.
- The expense pool definition: exactly what taxes, insurance, and CAM categories are recoverable.
- Caps and exclusions: any cap on controllable CAM, and the list of excluded costs such as capital items and ownership expenses.
- The reconciliation and audit-rights clause: when the true-up happens and the window the tenant has to dispute it.
Miss any of these and the abstract understates what the lease really costs. Leaseabstracts pulls each one from the lease PDF, source-linked to the clause, so a landlord's rent roll or a tenant's audit starts from the actual document. See how it works.
Triple net lease FAQ
What is a triple net lease?
A triple net lease is a commercial lease where the tenant pays base rent plus a pro-rata share of the property's real estate taxes, building insurance, and common area maintenance. The landlord receives rent that is close to net of operating costs, because the tenant reimburses those three expense categories on top of rent.
What does NNN mean?
NNN stands for the three nets a tenant pays in a triple net lease: net of taxes, net of insurance, and net of common area maintenance. A quote of "$22 per square foot NNN" means $22 base rent plus the tenant's share of those three costs, which are billed separately and reconciled to actual each year.
How is triple net calculated?
NNN charges equal the tenant's pro-rata share multiplied by the building's recoverable expense pool. Pro-rata share is the tenant's square footage over the building's rentable area. A 10 percent tenant in a building with a $500,000 annual pool owes $50,000 a year, billed monthly as an estimate and trued up after year-end.
What is the difference between a gross lease and a triple net lease?
In a gross lease the landlord pays the operating costs out of a higher base rent, so the tenant's payment is stable. In a triple net lease the tenant pays a lower base rent plus taxes, insurance, and CAM directly, so the total moves with actual costs. A gross rent and an NNN rent are only comparable once you add the nets to the NNN figure.
What are the disadvantages of a triple net lease for a tenant?
The tenant carries the variable costs, so a tax reassessment, an insurance spike, or an uncapped CAM pool raises the bill with little warning. The quoted rent also understates the true occupancy cost. Tenants manage this by negotiating a cap on controllable CAM, a clear exclusions list, and an audit right, then checking every annual reconciliation against the lease.