Commercial Rent Calculator
Convert a quoted rate per square foot into real money — with the load factor, the triple-net load and the escalations that turn a headline rate into an effective one.
Commercial Rent Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Effective rent is undiscounted; a present-value calculation will differ.
- NNN figures are estimates subject to annual reconciliation against actual cost.
- Excludes tenant improvement allowances, parking and after-hours HVAC.
In short: A 32.00 base rate on 4,200 usable feet is not 134,400. A 15% load factor makes it 4,830 rentable feet and 154,560, and an 8.70 NNN load takes the all-in cost to 196,581 a year.
Formula
rentable = usable × (1 + load factor)
annual all-in = rentable × (base + tax + insurance + CAM)
[('usable', 'the area you can occupy'), ('load factor', 'your share of common areas'), ('NNN', 'tax + insurance + CAM, per sq ft per year'), ('effective rate', 'net of free rent, inclusive of escalations')]
Worked Example
- Gross up usable area by the load factor to get rentable area.
- Multiply rentable area by the base rate.
- Add the triple-net load per square foot.
- Divide by twelve for the monthly payment.
- Restate everything per USABLE foot to compare buildings.
4,200 usable feet with a 15% load is 4,830 rentable — 630 feet you pay for but cannot occupy. At 32.00 base the annual base rent is 154,560, or 12,880 a month. Adding 4.20 tax, 1.10 insurance and 3.40 CAM gives an 8.70 NNN load, 27.19% of base, taking the all-in figure to 196,581 a year and 16,381.75 a month. Per usable foot that is 46.81, not the 32.00 quoted. Over five years with 3% escalations and three months free, the effective base rate is 32.38.
Strengths & Limits Of This Model
Where this engine is strong
- Separates usable from rentable and prices the difference
- Restates everything per usable foot for honest comparison
- Values free rent against escalations over the full term
Where it stops
- Undiscounted effective rent
- No TI allowance modelling
Practical Use Cases
Comparing two buildings
Reducing both to all-in cost per usable foot.
Budgeting an office move
Getting the monthly outgoing including NNN.
Negotiating a letter of intent
Valuing free rent against a lower face rate.
Checking a load factor
Seeing exactly how much unoccupiable area you fund.
Modelling a five-year commitment
Totalling rent with escalations across the term.
Methodology & Editorial Standards
Rentable area is usable grossed up by the load factor, which is the convention used in the overwhelming majority of United States office leases. Base and triple-net components are both applied per rentable foot. The effective rate totals base rent across the term with compounding escalations, deducts the value of the free-rent period at the year-one rate, and divides by the term in years — an undiscounted average rather than a net present value, which is the standard broker convention.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Commercial Rent Calculator — 10 Expert FAQs
10 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How is commercial rent calculated?
Rate per square foot per year, multiplied by the RENTABLE area, then divided by twelve for the monthly figure. Under a triple-net lease you add tax, insurance and common area maintenance on top, and those are reconciled annually against the landlord's actual costs rather than fixed.
What is a load factor?
The gross-up that converts usable area into rentable area, representing your share of lobbies, corridors, restrooms and plant. Ten to twenty per cent is typical. It means the area you pay for always exceeds the area you can occupy, and two buildings quoting the same rate can differ materially in real cost because of it.
What does triple net mean?
The tenant pays property tax, building insurance and common area maintenance in addition to base rent — the three nets. A gross lease bundles them into one figure instead. A 32 NNN quote and a 40 gross quote can describe almost the same deal, which is why the structure must be established before any comparison.
Is rent quoted per year or per month?
Both conventions exist, and they differ by a factor of twelve. Most United States office markets quote annually per square foot; several markets, including much of California's retail sector, quote monthly. Establish which one you are looking at before anything else in the negotiation.
How do I compare two spaces fairly?
Reduce each to total annual cost per USABLE square foot, including the NNN load. That single number strips out differences in load factor, quoting convention and lease structure, and it is frequently the only way to see that the cheaper-looking quote is the more expensive space.
What is an escalation clause?
A contractual annual increase in base rent, commonly two to four per cent or linked to an inflation index. It compounds, so the final year of a ten-year lease can be well above the first. The effective rate across the whole term is the figure to negotiate against, not the year-one rate.
Why would a landlord give free rent instead of a lower rate?
Because the face rate sets every subsequent year, drives the escalation base, and feeds directly into the building's own valuation, whereas free rent is a one-off concession that leaves all of that intact. A tenant should therefore value the two on an effective-rate basis rather than treating free months as a gift.
Are CAM charges capped?
Sometimes, and it is worth negotiating for. Caps may apply to controllable expenses only, excluding tax and insurance, and may be annual or cumulative. Without a cap, common area maintenance can rise faster than your base rent escalation and quietly undo whatever you negotiated on the face rate.
What is a tenant improvement allowance?
A contribution from the landlord toward fitting out the space, usually quoted per rentable square foot. It is economically equivalent to free rent and should be valued the same way, by spreading it across the term and netting it off the effective rate rather than treating it as separate.
Does the load factor apply to NNN charges too?
Generally yes, because the charges are levied per rentable square foot on the same basis as base rent. That means the load factor magnifies the whole occupancy cost, not just the base component — which is why a high load factor in a high-NNN building is more expensive than it first appears.