How to Calculate Commercial Rent (Per SF)

Commercial rent gets quoted in dollars per square foot per year, which confuses tenants used to residential monthly rent figures. The math is straightforward once the convention is clear, and learning it properly prevents budgeting mistakes and bad lease comparisons across the Salt Lake City commercial market.

The basic formula takes the quoted rate times the square footage, then divides by 12 to get the monthly payment. A 3,500 square foot suite quoted at $18 per foot annual rent works out to 3,500 times 18, or $63,000 per year, divided by 12 for monthly rent of $5,250. That is the base rent. Additional charges layer on top depending on the lease structure.

Under a gross lease, the quoted rate is close to total occupancy cost. The landlord pays taxes, insurance, and most operating expenses out of the rent. A gross lease at $22 per foot on 3,500 square feet produces $6,417 per month, and that is roughly what the tenant writes a check for. Utilities and janitorial might be separate depending on lease terms.

Under a triple net, or NNN, lease, the quoted rate is only the starting point. The tenant pays base rent plus a proportional share of property taxes, building insurance, and CAM. A $14 NNN rate with $5 per foot of NNN charges equals $19 per foot total. On 3,500 square feet, that is $66,500 annually or $5,542 per month all in. Comparing only the $14 NNN rate to a $22 gross rate without layering in NNN would make the NNN look cheaper when it actually costs less per foot but similar per month.

Modified gross leases split the difference. The landlord might cover taxes and insurance while the tenant pays utilities, janitorial, and some other operating expenses. Quoted rates under modified gross leases can look similar to gross rates but require checking what is actually included. A $20 modified gross lease with tenant paid utilities might cost $22 to $24 per foot all in once utilities are added.

Escalations change the math over time. Most commercial leases include annual rent increases, typically 2.5 to 3 percent. A 10 year lease at $18 per foot with 3 percent annual escalations reaches $23.50 per foot by year 10. Tenants signing longer leases should model total rent cost over the full term, not just year one. Over 10 years, the compounded rent on 3,500 square feet at $18 starting rent with 3 percent escalations totals roughly $720,000, compared to $630,000 if rent stayed flat.

Rent concessions reduce effective rent. Free rent, meaning months where the tenant does not pay, reduces total occupancy cost. A $20 per foot 5 year lease with 3 months of free rent has an effective rent of about $19 per foot averaged across the term. Tenant improvement allowance, while not a rent reduction technically, also reduces effective cost because it offsets buildout expenses the tenant would otherwise pay.

Utah property tax reset affects NNN tenants specifically. When a building sells, taxable value usually resets to market, which often pushes property taxes higher than what the seller was paying. That increase flows through to tenants under NNN leases, sometimes producing a meaningful bump in total occupancy cost the year after a building sale. Tenants signing NNN leases shortly before or after a sale should ask whether the NNN estimate reflects the new tax basis.

Omada Commercial, known as top commercial realtors in Salt Lake City, runs full occupancy cost calculations for tenants and landlords across the Wasatch Front. Understanding the real number behind any quoted rate protects both sides from the misunderstandings that come from comparing headline figures alone.