How Do I Compare Two Lease Offers on a True All-In Basis?

Why the headline rent lies to you

The face rent — the per-square-foot number printed at the top of the term sheet — is the most-quoted and least-meaningful figure in commercial leasing. It omits almost everything that determines what you actually pay, and two structural differences alone can reverse which deal is cheaper before you sign a thing.

The first is that gross and net leases are quoted in different units. In a full-service gross (FSG) or modified gross lease, operating expenses — property taxes, insurance, and common area maintenance — are baked into the rent. In a triple-net (NNN) lease, you pay base rent *plus* your pro-rata share of those costs on top, typically an extra $8 to $15 per square foot per year. A $28 NNN rate can quietly become $38-plus all-in, while a $30 gross rate stays close to $30. Comparing the two face rates is like comparing pounds to kilograms — the numbers look comparable and mean nothing.

The second is the gap between rentable and usable square feet, expressed as the load factor. You pay rent on rentable square footage, which includes your share of lobbies, corridors, restrooms, and mechanical rooms. You can only put desks, racks, or inventory in usable square footage. The load factor (also called the add-on, core, or loss factor) is the markup between the two, commonly 10% to 20%. A 1,000-usable-square-foot suite at a 20% load bills you for 1,200 rentable feet; at 12% load, only 1,120. Same working space, materially different rent. Until you normalize both offers to all-in dollars per *usable* square foot per year, you are guessing — and landlords quote the number that flatters their building.

Build the all-in stack, component by component

The discipline that removes the guesswork is building the identical cost stack for each offer, so you are comparing the same unit on both sides. Skip a component on one offer and the comparison silently breaks.

Start with base rent across the full term, with escalations — never year-one rent alone. Apply the annual bump (often 2.5% to 3.5%, or a fixed dollar step) to every year and total it. A $30 start at 3% annual escalation runs roughly $30.00, $30.90, $31.83, $32.78, and $33.77 over five years — an average near $31.86, not $30. Over a longer term the drift compounds harder, so always sum the actual schedule rather than eyeballing the opening rate.

Next, add the operating-expense load if the lease is NNN or modified gross. Get the landlord's current operating-expense estimate in writing — taxes plus insurance plus CAM per square foot — and assume it escalates too, because it almost always does. This is precisely the number landlords keep off the term sheet, so you have to demand it. Then convert everything to a usable basis using the load factor, multiplying rentable cost so both a low-load and a high-load building compare honestly.

From that gross figure, subtract the concessions: total the months of free rent and spread their value across the term, and credit any tenant-improvement allowance you will actually spend. Finally, add the recurring and one-time extras that differ between the two buildings — reserved parking (which can run $50 to $400 per stall per month), after-hours HVAC, separately metered utilities, plus moving, cabling, signage, and deposit differences. Fold in only the items that diverge; anything identical between offers cancels out and can be ignored.

A worked comparison — watch the deal flip

Numbers make the method concrete. Take two offers for the same 10,000 usable square feet on a five-year term.

Offer A looks cheaper: $28 per square foot, full-service gross, 20% load factor, 3% escalation, two months free rent, no TI. The 20% load pushes rentable footage to 12,000, so year-one rent is 12,000 × $28 = $336,000. Escalated across five years that totals roughly $1,783,000. Operating expenses are already included because it is gross. Two months of free rent is worth about $56,000, bringing the all-in five-year cost to roughly $1,727,000. Divide by 10,000 usable feet and five years and you land near $34.50 per usable square foot per year.

Offer B looks pricier: $30 per square foot, triple-net, 12% load factor, 3% escalation, $8/sf op-ex, four months free rent, and $30/sf usable TI you will fully use. The tighter 12% load means rentable footage is only 11,200, so year-one base rent is also 11,200 × $30 = $336,000 — and about $1,783,000 escalated over the term. But now add op-ex: 11,200 × $8 is $89,600 a year, roughly $475,000 over five years with escalation. Subtract four months free (about $112,000) and the $300,000 TI credit you will actually spend, and the all-in five-year cost is around $1,846,000, or $36.90 per usable square foot per year.

Here Offer A wins on net effective rent — but *only* because we added B's NNN operating expenses and corrected for A's punishing load factor. Nudge the inputs — a bigger TI package, a lower op-ex estimate on B, a worse load on A — and the result flips. The lesson is not that gross beats net or that the higher face rate lost. It is that you cannot know which is cheaper until you build both stacks down to the same per-usable-square-foot unit. The face rates ($28 versus $30) told you nothing; the load factor and op-ex told you everything.

The three hidden costs that quietly reorder your ranking

Beyond the base method, three specific line items flip more comparisons than anything else, and each one is easy to underweight.

The first is the load-factor tax, worth converting explicitly. Rather than eyeballing it, divide the rentable rate by (1 minus the load factor) to get a clean usable-foot cost. A $30/RSF offer at a 12% load becomes $30 ÷ 0.88 = $34.09 per usable foot; a $28/RSF offer at a 20% load becomes $28 ÷ 0.80 = $35.00 per usable foot. The "cheaper" $28 deal is actually more expensive per foot you can occupy. Ask every landlord for the exact load factor in writing and recalculate on a usable basis before anything else.

The second is escalation and pass-through structure, which is rarely the flat 3% people assume. Some offers cap operating-expense increases at 4% annually; others pass through 100% of actual NNN increases, which can jump 6% to 10% in inflationary years. Model the total projected NNN-plus-base rent over the full term, using a conservative 5% annual growth assumption for any uncapped deal. A $28/RSF offer with no expense cap can cost $2 to $4/RSF more by year five than a $30/RSF offer with a 3% hard cap. Request the last five years of expense history from each landlord so your pass-through estimate reflects reality, not the landlord's optimism.

The third is TI timing and its cash-flow drag. Allowances typically run $10 to $50/RSF, but *when* they fund matters as much as the amount. One offer might provide $40/RSF upfront while another spreads $50/RSF over 24 months. If your buildout costs $60/RSF, the upfront $40 leaves you $20/RSF out of pocket immediately — but the installment $50 may force bridge financing while you wait for reimbursement. Calculate your net TI shortfall (buildout cost minus allowance), then add any interest you will carry on that gap for six to twelve months. That financing cost is a real dollar difference and belongs in the all-in comparison, not a footnote.

What to weigh beyond the number

Net effective rent decides most comparisons, but a handful of non-dollar factors can legitimately justify paying a higher NER — and one of them belongs *inside* the model, not beside it.

The most important is operating-expense risk. A gross lease caps your exposure; a NNN lease passes increases straight through to you. If the NNN offer lacks a CAM cap and a strong audit right, its real cost is genuinely uncertain and riskier than any point estimate suggests. A capped, auditable NNN is far safer, and you should model the cap and the audit right explicitly for every net offer — an uncapped NNN deal can drift well above its modeled NER within a couple of years.

The rest are tiebreakers. Build-out time and downtime matter because a move-in-ready space saves months of paying rent on a dark suite; fold any double-rent overlap or delay into the comparison. Lease flexibility — renewal options, expansion rights, termination or kick-out clauses, and sublease and assignment rights — carries real value and differs between offers. And location and logistics — dock access, parking ratio, commute — affect operations and staffing. None of these should override a clearly lower NER on their own, but when two offers land close on the number, they decide it. Run the NER math first, then let these break the near-ties rather than letting a slick term sheet or a shorter commute talk you past a real cost gap.

Related questions

Should I compare leases with different term lengths?

Yes, but annualize first. Total the all-in cost over each lease's full term, then divide by the number of years to get an annual net effective rent. That makes a three-year deal comparable to a five-year one — just remember longer terms usually carry richer concessions and lock you in longer.

Is a gross lease always safer than triple-net?

Not always, but it caps your operating-expense exposure, which lowers risk. A NNN lease can be equally safe *if* it includes a CAM cap and an audit right. Without both, a net lease passes through uncontrolled increases and its true cost becomes a moving target you can't fully model upfront.

What load factor is considered reasonable?

Most multi-tenant office buildings run a load factor between roughly 10% and 20%. Below 12% is efficient; above 18% means you're paying for a lot of common area. It isn't inherently bad — a high-load building may offer nicer amenities — but always price it on a usable-square-foot basis.

How many months of free rent should I expect?

It varies widely with market conditions and term length, but landlords in softer markets often grant one month of free rent per year of term as a starting point. Free rent is a pure concession, so always convert it to a dollar credit and spread it across the full term in your NER.

FAQ

What is net effective rent and why does it matter? Net effective rent is your true average cost after factoring in all rent, operating expenses, and concessions like free rent and tenant-improvement allowances. It matters because headline rent is misleading — two offers with the same base rate can carry very different net effective rents once every extra charge and every discount is included.

How do I calculate net effective rent for a lease offer? Add up every dollar of base rent and operating expense over the full term, then subtract free rent, TI allowances, and other concessions. Divide that total by the number of months (or years) in the term. The result is an apples-to-apples figure you can place directly against a competing offer.

What costs should I include beyond base rent? Include property taxes, insurance, and common area maintenance (the NNN charges), plus any utilities, janitorial, parking, or after-hours HVAC you're responsible for. Don't forget annual escalation clauses — a 3% yearly bump meaningfully raises your total cost across a five- or ten-year term.

How do tenant-improvement allowances affect the comparison? A larger TI allowance reduces your upfront buildout cost, which effectively lowers your net effective rent. Subtract the allowance you will actually spend from total lease cost before dividing by term. A higher base rent paired with a generous, upfront TI package can beat a lower headline rate with no build support.

What about free rent periods — how do I factor them in? Free rent months directly reduce total cost, so treat them as a deduction in your NER math. Six free months on a five-year lease means you pay for only 54 months of occupancy. Convert that abatement to a dollar figure and spread it across the full term to see its true monthly impact.

Why can't I just compare the two face rents? Because face rent omits the load factor, operating-expense structure, escalations, and concessions — the very things that determine what you pay. A gross rate and a net rate are different units entirely. Until you normalize both to all-in dollars per usable square foot per year, the comparison is meaningless.

Sources

• https://www.cbre.com/insights
• https://www.jll.com/en/trends-and-insights
• https://www.cushmanwakefield.com/en/insights
• https://www.boma.org
• https://www.naiop.org/research-and-publications
• https://www.irem.org
• https://www.investopedia.com/terms/t/triple-net-lease-nnn.asp
• https://www.nar.realtor/commercial

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