Types of Commercial Leases Explained: Gross, Modified Gross, Net, NNN, and What Each One Actually Costs You
Two tenants. Same building. Same square footage. Same base rent per square foot.
Different lease types. One pays $4,800 a month and nothing else. The other pays $4,800 a month plus taxes, insurance, maintenance, CAM charges, HVAC repairs, and roof reserves. Their actual monthly cost: $7,100.
The lease type is the framework that determines who pays for what beyond base rent. It’s one of the first things to understand about any commercial lease — because the label alone (gross, NNN, modified gross) tells you almost nothing about your real cost. The actual terms inside the lease tell you everything.
This post explains each major commercial lease type, what it means for your total occupancy cost, and the questions to ask regardless of which structure you’re offered.
If you want to know exactly how your lease allocates costs between you and the landlord, run it through sasir.ai — our AI-powered lease analysis tool. The first scan is free.
The Core Framework: Who Pays for What
Before diving into specific lease types, the underlying question every tenant needs to answer is: beyond base rent, what am I responsible for?
Commercial property costs fall into several categories: property taxes, building insurance, common area maintenance (CAM), utilities, repairs and maintenance, and property management fees. Depending on the lease type, these costs may be paid entirely by the landlord (and built into a higher base rent), entirely by the tenant (on top of a lower base rent), or split in various ways between the two parties.
The lease type label is shorthand for how those costs are allocated. But the shorthand is imprecise — there is no universal standard for what ‘gross’ or ‘modified gross’ or ‘net’ means. Two leases with the same label can allocate costs very differently. This is why reading the actual lease language always matters more than the label.
Gross Lease (Full-Service Lease)
In a gross lease — sometimes called a full-service lease — the tenant pays a single flat rent amount and the landlord covers most or all building operating costs from that rent: taxes, insurance, maintenance, and utilities.
The tenant’s cost structure is highly predictable. The base rent is the total rent. Budgeting is straightforward.
The tradeoff: gross lease base rents are typically higher than net lease base rents, because the landlord is absorbing the operating cost risk. And most gross leases include escalation clauses that allow base rent to increase annually — which means the operating cost certainty you’re paying for can still erode over time.
Gross leases are common in multi-tenant office buildings, co-working environments, and some medical office settings. They are rare in retail and industrial leases.
A gross lease with a 5% annual escalation still compounds your cost significantly over a multi-year term. The structure is predictable; the long-term math still requires modeling.
Net Lease (Single, Double, Triple Net)
Net leases shift some or all operating costs from the landlord to the tenant, on top of base rent. The three common variants:
Single net (N): the tenant pays base rent plus property taxes. The landlord pays insurance and maintenance. Relatively uncommon as a standalone structure.
Double net (NN): the tenant pays base rent plus property taxes and building insurance. The landlord remains responsible for maintenance and structural repairs. More common, especially in older commercial buildings.
Triple net (NNN): the tenant pays base rent plus property taxes, building insurance, and maintenance — essentially all operating costs. This is the most common structure in retail and freestanding commercial properties. It gives the landlord the most predictable cash flow (net of all expenses) and passes the most cost variability to the tenant.
The appeal of a NNN lease from the tenant’s perspective: base rent is typically lower than in a gross lease, which makes the headline number look attractive. The risk: operating costs can vary significantly year to year, and uncapped NNN leases expose the tenant to expenses they cannot fully predict or control.
The most important due diligence question before signing a NNN lease: what have operating costs been over the past three years, and what is the trend? Request historical CAM, tax, and insurance data from the landlord before you sign. The headline rent is only part of the picture.
Modified Gross Lease
A modified gross lease sits between a true gross lease and a NNN lease. Some costs are covered by the landlord (included in base rent) and others are passed to the tenant separately. The specific allocation varies by property and negotiation.
Common modified gross structures:
Tenant pays base rent plus utilities, landlord covers taxes, insurance, and maintenance
Tenant pays base rent plus their proportionate share of CAM increases above a base year, landlord covers the base-year amount
Tenant pays base rent plus property taxes, landlord covers insurance and CAM
Modified gross leases require the most careful reading because ‘modified gross’ is not a standard term. Two leases can both be called modified gross and allocate costs very differently. The only way to know your actual cost structure is to read what the lease actually says about each specific expense category.
Base year provisions are particularly important in modified gross leases. The base year sets the benchmark for operating cost pass-throughs. If the base year is unusually low (e.g., a year with low occupancy or deferred maintenance), future pass-throughs will be higher than expected.
Absolute Net Lease (Bondable Lease)
An absolute net lease — sometimes called a bondable lease — is the most tenant-responsible structure. The tenant pays base rent plus all building costs, including structural repairs, roof replacement, and major capital expenditures. There are essentially no landlord obligations under an absolute net lease.
These leases are most common in single-tenant, long-term situations such as sale-leaseback transactions, freestanding retail with creditworthy national tenants, and institutional commercial real estate. For most small and mid-sized business tenants, an absolute net structure is unusual and worth scrutinizing carefully.
Total Occupancy Cost: The Number That Actually Matters
Regardless of lease type, the number every tenant should calculate before signing is total occupancy cost — the all-in monthly expense of operating in the space.
How to calculate it:
Start with base rent
Add CAM charges and operating expense pass-throughs
Add property tax and insurance allocations (if applicable)
Add utilities (if not included)
Add any management or administrative fee
Project escalations over the full term
Compare total to projected revenue
If the total occupancy cost at year five or year ten represents more than 10 to 15 percent of your projected revenue, the lease may be front-loaded in a way that creates sustainability risk. The headline rent is the starting point. Total occupancy cost is the decision number.
The base rent is what landlords market. The total occupancy cost is what you actually pay. Always calculate one before you commit to the other.
What to Ask Regardless of Lease Type
What is the total occupancy cost at year one, year three, and year five?
What historical operating costs look like — request three years of actuals for any net or modified gross lease
What costs are capped vs. uncapped — and what the cap structure looks like
What is included in the base year for modified gross or expense stop structures
How management and administrative fees are calculated and what they cover
Whether capital expenditures are passed through CAM or kept as landlord obligations
The Bottom Line
Gross, modified gross, net, NNN — these labels are starting points, not definitions. Two leases with the same label can produce very different total occupancy costs. The label tells you nothing about whether costs are capped, what the base year is, or whether capital expenses flow through to you.
Read the cost allocation provisions. Calculate total occupancy cost. Compare to revenue. Then decide.
If you’re navigating a commercial lease, these additional resources may help:
Triple Net Lease Explained: What NNN Really Costs and What Most Tenants Get Wrong
CAM Charges Explained: What They Are, What’s Hiding Inside, and How Most Tenants Overpay
If you want to know exactly how your lease allocates costs between you and the landlord, run it through sasir.ai. The first scan is free.
