What is one tenant’s triple-net share?

In a triple-net lease the tenant pays base rent plus its share of the three "nets": property taxes, property insurance, and common area maintenance (CAM). The landlord passes those operating costs through to tenants rather than absorbing them in the rent. Leases that pass through only one or two of the three are sometimes called single-net or double-net, so check which costs your lease actually lists.

Most leases use a pro-rata share: the tenant's rentable square footage divided by the property's total rentable square footage. A 3,000 sq ft space in a 45,000 sq ft center has a 6.67% share. Some leases define the denominator differently, such as leased or occupied area instead of total area, or exclude an anchor that pays its own costs, so use the lease's exact definition before relying on the result.

Enter the number of months the tenant occupied the space. Each expense is multiplied by the pro-rata share and then by the months occupied divided by 12, so a tenant there for 6 months is allocated half a year's share. It works in whole months; if the lease prorates by the day, adjust the result by hand.

If a tenant occupied for six months, its allocation is already prorated to half the annual expense. Dividing that by six shows the realistic monthly estimate the tenant actually experienced, rather than an artificially low twelfth. Each line is rounded to whole dollars separately, so the monthly total can differ by a dollar or two from the annual total divided by the months.

A common approach is to start from this year's actual share, adjust for anything you already know will change, such as a new tax assessment or an insurance renewal quote, and divide by 12. Many leases let the landlord revise estimates once a year, and some require written notice first. Setting estimates close to the real cost keeps the year-end true-up small for both sides.

Often, yes. Leases that cap yearly increases usually cap only controllable CAM costs such as landscaping, janitorial, and repairs, while taxes and insurance pass through in full because the landlord can't control them. Taxes can also be billed on the tax authority's schedule rather than in monthly estimates. This calculator treats all three costs the same way, so apply any lease-specific rules separately.

Caps on controllable expenses, base-year expense stops, excluded cost categories (capital items, leasing costs, management fees beyond an allowed percentage), administrative fees, and vacancy gross-ups. Each of those is lease-specific. The CAM reconciliation calculator handles a year-over-year cap on CAM.

Most leases call for an annual statement showing the property's actual costs for each category, the tenant's share percentage, the amount allocated to them, the estimates they paid, and the resulting balance. Keeping the tax bill, insurance invoice, and CAM ledger behind each figure makes it much easier to answer questions. The CSV download from this calculator lays out the same figures for one tenant.