Rent Per Square Foot Calculator
Commercial rent is quoted per square foot per year in most of the US. Multiply the rentable square footage by the rate to get annual rent, then divide by twelve for the monthly figure. A 2,300 sq ft suite at $32 per square foot is $73,600 a year, or $6,133 a month.
Rent Per Square Foot Calculator
Rentable versus usable square feet, and the load factor
The single most misunderstood number in commercial leasing is which square footage you are paying for. Usable square feet is the space inside your suite — what you can put desks in. Rentable square feet adds your share of the building's common areas: lobbies, corridors, shared restrooms and mechanical rooms.
The gap between them is the load factor, sometimes called the common area factor or add-on factor. It is expressed as a percentage, and rentable equals usable times one plus the load factor. A 2,000 sq ft suite with a 15% load factor is billed as 2,300 rentable square feet, so you pay rent on 300 square feet you cannot furnish.
Load factors typically run 10 to 20%. A single-tenant building can be close to zero; a multi-tenant tower with generous lobbies and long corridors can exceed 20%. This is why comparing two quotes on headline rate alone is misleading: a $30 rate at a 12% load factor costs less per usable foot than a $28 rate at a 22% load factor.
Worked comparison — Suite A is 2,000 usable at $30/sq ft with a 12% load factor. Rentable is 2,240, so annual rent is $67,200, which is $33.60 per usable square foot. Suite B is 2,000 usable at $28 with a 22% load factor. Rentable is 2,440, annual rent $68,320, or $34.16 per usable foot. The cheaper-looking suite costs more.
| Usable sq ft | Load factor | Rentable sq ft | Rate / sq ft / yr | Annual rent | Monthly rent |
|---|---|---|---|---|---|
| 1,000 | 10% | 1,100 | $28 | $30,800 | $2,567 |
| 1,500 | 12% | 1,680 | $30 | $50,400 | $4,200 |
| 2,000 | 15% | 2,300 | $32 | $73,600 | $6,133 |
| 3,000 | 15% | 3,450 | $35 | $120,750 | $10,063 |
| 5,000 | 18% | 5,900 | $38 | $224,200 | $18,683 |
Gross, modified gross and triple net
Two quotes at the same rate can mean very different money depending on the lease structure, and the structure is often buried in a single line of the term sheet.
A gross lease bundles operating expenses into the rate. You pay one number and the landlord covers taxes, insurance, and common area maintenance. It is simple to budget and usually carries the highest headline rate.
A triple net lease, written NNN, excludes those three costs. The quoted rate covers the space only, and you pay taxes, insurance and CAM on top, usually as an additional per-square-foot charge. Those commonly add $5 to $12 per square foot, which can be a third of the total occupancy cost. A $22 NNN rate and a $32 gross rate can land in the same place.
Modified gross sits between the two, with some expenses included and others passed through. Because there is no standard split, the only way to compare a modified gross quote is to ask for the estimated total occupancy cost per square foot for the coming year.
Whatever the structure, compare on total annual cost per usable square foot. That single figure normalises the rate, the load factor and the expense structure, and it is the number that tells you what a suite actually costs your business.
Space per employee and sizing a suite
Working out how much space you need is the other half of the calculation, and it starts from headcount rather than from a floor plan.
Densities vary widely by how a business works. Traditional private-office layouts run around 200 to 250 usable square feet per person. Open plan with assigned desks runs 125 to 175. Hot-desking and hybrid schedules push it lower still, often 75 to 125 per person based on peak occupancy rather than headcount.
Worked example — a 20-person team on an open-plan layout at 150 usable square feet per person needs about 3,000 usable square feet. At a 15% load factor that is 3,450 rentable square feet, and at $35 per square foot per year the rent is $120,750 annually, or $10,063 a month before operating expenses.
Add circulation and shared space to the headcount figure rather than assuming it is included. Meeting rooms, a kitchen and a reception area are typically 20 to 30% on top of the desk count, and in a hybrid office they often grow rather than shrink, because the space is used for collaboration instead of desks.
Step-by-step measurement guide
Confirm which square footage the rate applies to
Landlords quote against rentable square feet, not the space you can actually occupy. Ask for both the usable and rentable figures before comparing two suites.
Check whether the rate is annual or monthly
Most US markets quote dollars per square foot per year. Some, particularly in parts of the West Coast and in industrial leasing, quote per month. A $3 rate is cheap annually and expensive monthly.
Multiply rentable area by the rate
2,300 rentable square feet at $32 per square foot per year is $73,600 annually. Divide by twelve for the monthly figure: $6,133.
Add the operating expenses
Ask whether the quote is gross or triple net. A triple net rate excludes taxes, insurance and common area maintenance, which commonly add $5 to $12 per square foot on top.
Pro tips
Always ask for both square footages
Get the usable and the rentable figure in writing, plus the load factor. A quote that only mentions one number is hiding the other, and the difference is money you pay every month.
Annual or monthly changes everything
Most US markets quote per square foot per year, but not all. Confirm which before comparing: the same numeric rate is twelve times apart depending on the answer.
Compare on cost per usable square foot
Normalise every offer to total annual occupancy cost divided by usable square feet. That single number folds in the rate, the load factor and the expense structure.
Budget for the NNN add-ons
Taxes, insurance and common area maintenance commonly add $5 to $12 per square foot on a triple net lease. Ask for the current year's actual figures, not an estimate from the marketing sheet.