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Rentable vs usable area calculator
Office and multi-tenant leases charge rent on rentable area, which includes a share of the building's common areas, while the tenant occupies the usable area. Enter the usable area and the add-on factor (or the rentable area if you know it) to see the rentable area, the rent and what each usable square foot really costs. Nothing leaves your browser.
Results
- Rentable area
- 9,520 sq ft884.4 m²
- Add-on factor
- 12.0%
- R/U ratio
- 1.120
- Annual net rent
- $228,480
- Annual additional rent
- $138,040
- Gross rent per year
- $366,520
- Gross rent per month
- $30,543.33
- Net rent per usable sq ft
- $26.88 / sq ft / yr
- Gross cost per usable sq ft
- $43.12 / sq ft / yr
Arithmetic only: the lease and its measurement standard define the areas. Works in Canadian or US dollars. Calculated in your browser; nothing is sent or saved.
How it’s calculated
- Rentable area
Rentable = usable × (1 + add-on factor) - Add-on (load) factor
Add-on factor = rentable ÷ usable − 1 (the R/U ratio is rentable ÷ usable) - Cost per usable sq ft
Rent per usable sq ft = rent per rentable sq ft × rentable ÷ usable
Worked example (illustrative numbers)
- A tenant needs an office suite of 8,500 usable sq ft on a floor with a 12% add-on factor, so the rentable area is 8,500 × 1.12 = 9,520 sq ft.
- Asking rent is $24.00 net plus $14.50 additional rent per rentable sq ft: annual net rent $228,480 and additional rent $138,040, so $366,520 a year or $30,543.33 a month.
- Per usable square foot the tenant pays $26.88 net and $43.12 gross.
- If the landlord quotes 22,400 rentable sq ft for a floor with 20,000 usable sq ft, the add-on factor is 12.0% (an R/U ratio of 1.12).
Illustrative figures for a fictitious suite; they are not market rents or typical add-on factors for any building or city.
Usable, rentable and gross area
Usable area is the space a tenant actually occupies inside its premises. Rentable area adds the tenant's share of common areas that serve it: on a multi-tenant floor the corridors, washrooms and lobbies, and in some measurement methods a share of the building's main lobby and service areas. The difference is expressed as an add-on factor (also called a load factor or gross-up) or as the R/U ratio.
How these areas are measured is set by the measurement standard named in the lease. For offices, the BOMA standards (ANSI/BOMA Z65.1 and its successors) are widely used in Canada and the US; industrial, retail and multi-family buildings have their own BOMA standards, and some landlords use their own definitions. The lease, not the brochure, decides which standard and version applies.
Why the add-on factor matters when comparing space
Two suites at the same asking rent can cost very different amounts per usable square foot if their buildings have different add-on factors. Converting every option to cost per usable square foot, as this calculator does, puts them on the same footing. Tenants also check how efficient a floor plan is: the usable area is what their furniture and staff need, so the rentable area is a result, not a requirement.
Single-tenant industrial buildings usually have little or no add-on, because the tenant occupies the whole building; multi-tenant office towers usually have the most. Ask the landlord for the measurement certificate or the area schedule when the add-on looks high.
Showing areas in a listing
Say which area a figure is: "9,520 sq ft rentable (8,500 usable)" is clear; "9,520 sq ft" is not. Quote rents per rentable square foot, as the lease will, and keep the same measure across the availability table, the floor plans and the rent figures. OfferingStack has separate fields for the building area, the rentable area and the available area; the rentable area is shown as its own metric when it differs from the building area, and operating costs per square foot use the rentable area when you give it.
Estimates for marketing and screening only. This is not an appraisal, a valuation opinion, a measurement certificate, or financial, legal or tax advice.
Questions
How do you calculate rentable square feet from usable?
Multiply the usable area by one plus the add-on factor. 8,500 usable sq ft with a 12% add-on factor is 8,500 × 1.12 = 9,520 rentable sq ft.
What is a load factor or add-on factor?
The percentage added to a tenant's usable area for its share of common areas. A 12% add-on factor means the tenant pays rent on 12% more area than it occupies. Some landlords quote it as an R/U ratio, here 1.12.
Is rent charged on rentable or usable area?
In most multi-tenant office and retail leases in Canada and the US, rent and additional rent are charged per rentable square foot. Check the lease for the area definition and the measurement standard.
Can the rentable area change during a lease?
It can if the building is remeasured or common areas change, and some leases allow it. Others fix the area for the term. The lease wording decides.
Is my data saved?
No. The calculation runs in your browser and nothing you type is sent to OfferingStack.
Related
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