NNN Lease vs. Gross Lease: What's the Actual Difference?

The difference comes down to one question: who pays the operating expenses?

In a gross lease, the landlord pays property taxes, building insurance, and maintenance. You pay one number — base rent — and that's it. In a triple net lease (NNN), you pay base rent plus your proportionate share of all three of those expense categories. The base rent is lower, but your total occupancy cost is higher and less predictable.

The Gross Lease

A gross lease is the simpler structure. You agree to a fixed monthly rent. The landlord uses that rent to cover their mortgage, taxes, insurance, and operating costs. You don't see any of those numbers and you don't pay them separately.

The advantage is predictability. You know exactly what you're paying every month. Your occupancy cost doesn't fluctuate based on a property tax reassessment or an insurance premium spike.

The disadvantage is that the landlord builds their expected operating costs — plus a buffer — into the base rent. You're paying for those expenses either way. You just don't see the calculation, and you can't audit it.

Gross leases are most common in office buildings, particularly multi-tenant office properties where managing individual tenant expense reconciliations is operationally impractical at scale.

The NNN Lease

A triple net lease separates base rent from operating expenses. You pay a lower base rent, then pay your proportionate share of property taxes, building insurance, and common area maintenance on top.

The advantage, in theory, is transparency. You see the actual tax bill, the actual insurance premium, the actual maintenance costs. If the landlord manages the property efficiently and keeps costs low, you benefit directly.

The disadvantage is variability and complexity. Property taxes can jump when the building sells or when local rates change. Insurance premiums rise after claims. CAM charges include whatever the landlord decides to include, unless the lease specifically excludes certain categories. Year-end reconciliations can produce surprise bills.

NNN leases are standard in retail, industrial, and single-tenant commercial properties.

The Math on a Real Example

A 2,000 square foot retail space is listed at $22/SF gross or $16/SF NNN with estimated NNN of $7/SF.

The gross lease at $3,667 may actually be cheaper than the NNN lease once actual operating costs are accounted for, even though the headline NNN number looked lower. The $500/month difference at $9/SF actual adds up to $6,000/year in unexpected occupancy cost.

Modified Gross: The Middle Ground

Most office leases and some retail leases use a modified gross structure that sits between the two. You pay a fixed base rent that includes operating expenses for a defined base year. In subsequent years, you pay your proportionate share of increases over that base year amount — but not the base year costs themselves.

This protects you from year-one surprises while sharing the risk of rising operating costs over the lease term. It's generally more tenant-friendly than a straight NNN lease on a long term, because your exposure is capped at the increase over baseline rather than the full operating cost stack.

Which Is Better for Tenants

Neither structure is inherently better. The gross lease offers predictability. The NNN lease offers lower base rent and potential savings if operating costs are well-managed.

What matters is understanding what you're actually agreeing to in either case. A gross lease with an aggressive annual escalation clause can end up costing more than a well-negotiated NNN lease with a CAM cap. A NNN lease with no exclusions and no cap can cost significantly more than a gross lease at a higher headline rate.

Before you sign either structure, run the numbers on total occupancy cost — base rent plus realistic operating expenses — over the full lease term. And scan the lease through LiabilityScore™ to see what the specific provisions actually say, not just what the listing advertised.