Net Leasable Area Calculator
Net leasable area (NLA) is the part of a building a landlord can actually rent out: the total building area minus every shared space no single tenant controls, such as lobbies, corridors, stairwells, lift shafts, shared restrooms and plant rooms. This calculator does that one subtraction cleanly, then shows what share of the building earns rent, because an 80 percent efficient building and a 60 percent efficient building with the same total area are very different investments.
The result is in the same unit as your two inputs. This calculator does not convert between square feet and square meters, so enter both areas in one unit. A certified measurement under a named standard (for example ANSI/BOMA Z65.1) is what a lease should rely on; this tool checks the arithmetic once those areas are known.
Quick Answer
A 50,000 sq ft building with 10,000 sq ft of common area has a net leasable area of 40,000.00 sq ft. That is a leasable share of 80.00%: four fifths of the building can be let, and at $25 per sq ft per year that area supports $1,000,000 of gross potential rent before vacancy and expenses.
Key takeaways
- NLA is a subtraction, not a survey: total area minus common area. The hard part is agreeing what belongs in each figure, not the arithmetic.
- The leasable share is the number investors compare. Two buildings with equal totals can differ by 20 points of efficiency, and rent follows the leasable part only.
- Net leasable area is not the same as BOMA rentable area. Rentable area adds a tenant’s share of common space back in through a load factor; this tool’s NLA leaves common space out entirely.
- Both inputs must be in the same unit and on the same measurement basis. The calculator does not convert units or reconcile standards for you.
- Quick Answer
- How to use the net leasable area calculator
- The formula, and what the two inputs must actually mean
- Worked example: a 50,000 sq ft office building
- Reading the leasable share: efficiency bands that mean something
- Net leasable area vs rentable, usable and gross area
- What competing calculators miss
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use the net leasable area calculator
Enter the total building area and the total common area in the same unit, then click Calculate. The result, the leasable share and an efficiency reading stay hidden until you calculate.
- Get the total building area: from a certified floor plan, a surveyor’s measurement report or the listing particulars. The pre-filled 50,000 is the worked example below.
- Add up the common area honestly: lobbies, shared corridors, stairwells, lift shafts, shared restrooms, plant and electrical rooms, concierge desks. If a space sits inside one tenant’s locked premises, it is not common area.
- Check the units match: both figures in square feet, or both in square meters. Mixing them is the single most common way this subtraction goes wrong, and no error message can catch it.
- Read all three outputs: the net leasable area itself, the leasable share as a percentage, and the efficiency reading. The percentage is what you carry into rent, yield and service-charge discussions.
The formula, and what the two inputs must actually mean
Net Leasable Area = Total Building Area − Common Area. The formula is trivial; the definitions are where leases are won and lost, because “total” and “common” change meaning with the measurement standard behind them.
Leasable share = Net leasable area ÷ Total building area × 100 | Common share = Common area ÷ Total building area × 100
The total is closest in spirit to a gross floor area: the whole measured floor plate, service spaces included. Under the office standard published as ANSI/BOMA Z65.1, that total is then split into usable area, floor service area, building service area and major vertical penetrations such as lift shafts and stairwells, which are excluded from rentable area altogether. The practical rule for this calculator is simple: anything every tenant shares, or that serves the whole building, goes in the common box; anything one tenant exclusively occupies stays out of it.
One honest warning about names. In much of the Australian and New Zealand market the same idea is called net lettable area, and surveyors there measure it under local guidance such as the Property Council method. In the UK and in IPMS-based reporting, the closest occupier figure is the exclusive-use area under IPMS 3, which the IPMS framework explained by ORS defines floor by floor. Same subtraction, different rulebooks for the inputs. Name the standard in the lease, or expect an argument at rent review.
Worked example: a 50,000 sq ft office building
The pre-filled example is a mid-size office building: 50,000 sq ft total, of which the lobby, cores, corridors, shared restrooms and plant take 10,000 sq ft. The calculator returns 40,000.00 sq ft of net leasable area, an 80.00% leasable share.
At a market rent of $25 per sq ft per year, that leasable area carries $1,000,000 a year of headline rent. Pricing the whole 50,000 sq ft by mistake would overstate the rent roll by $250,000, which is exactly the error a gross potential rent check built on NLA instead of total area avoids. The same subtraction, run on three more buildings, produces the checks below. Every row is a real run of this calculator.
| Building | Total area | Common area | Net leasable area | Leasable share |
|---|---|---|---|---|
| Office building (worked example) | 50,000 | 10,000 | 40,000.00 | 80.00% |
| Retail parade | 12,000 | 1,800 | 10,200.00 | 85.00% |
| Metric office floor plate, m² | 5,000 | 1,250 | 3,750.00 | 75.00% |
| Small mixed-use building, decimal survey | 1,250.5 | 250.25 | 1,000.25 | 79.99% |
Reading the leasable share: efficiency bands that mean something
The leasable share is the building’s efficiency in one number. Retail parades and simple industrial sheds run high, because tenants share almost nothing; deep-plan offices with grand lobbies, big cores and amenity floors run lower, by design.
| Leasable share | Reading shown by the calculator | What it usually means |
|---|---|---|
| 85% and above | Highly efficient | Retail, industrial and simple floor plates with minimal shared space |
| 75% to 84.99% | Efficient | A well-planned office building; the worked example sits here at 80.00% |
| 60% to 74.99% | Typical, check the common load | Large lobbies, amenity space or older cores are eating lettable floor |
| Under 60% | Common-heavy | Verify the inputs first; if they are right, the design carries a lot of non-earning space |
Efficiency also drives planning ratios beyond rent. The same total-to-usable relationship sits behind the floor to area ratio used in development appraisal, where what counts as floor area decides how much building a plot can carry. In both cases the lesson is identical: the definition of the area matters more than the division.
Net leasable area vs rentable, usable and gross area
Four area terms get used as if they were interchangeable, and they are not. The table below is the distinction this page’s readers most often need, because a lease quoted on rentable area and a valuation run on NLA will never agree.
| Measure | Includes common area? | Used for |
|---|---|---|
| Net leasable area (this tool) | No. Total area minus all common area | Building-level lettable stock, efficiency and yield analysis |
| Rentable area (BOMA) | Yes, a pro-rata share added back through a load factor | The area most North American office leases actually charge rent on |
| Usable (occupier) area | No, and measured only within one tenant’s premises | Space planning: what a tenant can actually furnish and occupy |
| Gross building area | Everything, including plant and parking levels in some conventions | Construction cost, insurance and planning |
The rentable row deserves one more sentence, because it is the source of most disputes. Under a modified gross lease and most other office leases, rent is charged on rentable area: usable area plus an allocated slice of the corridors and lobbies the tenant benefits from. That allocated slice is the load factor, and it can add 10 to 30 percent. This calculator deliberately does the simpler, building-level job: it tells you how much of the whole building is lettable at all. Do not sign a lease expecting its output to match a BOMA rentable figure for an individual suite; they answer different questions, and a surveyor’s report under a named standard, such as the teaching material in the UBC Sauder real estate programme’s BOMA review guide, is the document that settles suite-level numbers.
What competing calculators miss
The rival tools for this keyword fall into three groups, and each leaves a gap this page is built to close:
- Same subtraction, no context (BraveCalculator’s net leasable area page): total minus non-leasable, which is correct arithmetic, but the result arrives with no efficiency share, no efficiency reading and no warning that rentable area is a different number. A bare subtraction invites readers to use NLA where a lease expects a loaded rentable figure.
- A different question wearing a similar name (AreaCalculators’ net lot area page): that tool subtracts public area from a land parcel’s total lot area. Useful for development plots, useless for a building, and a real cannibalisation trap for searchers who type “net area” loosely.
- General net area tools (OwnCalculator): these do report a usable percentage, to their credit, but they frame the deduction as walls, ducts and service voids inside a single space, not as building-wide common area, and they never touch measurement standards, load factors or what a tenant can dispute.
- BOMA load-factor calculators (Calculator City and similar): strong on the opposite direction, loading a tenant’s usable area up to a rentable figure, but they assume you already know your usable and common splits. None starts from the whole building and answers the owner’s first question: how much of this building can be let at all?
- The gap this page fills: the building-level subtraction, the leasable and common shares, an efficiency reading with stated bands, an explicit NLA-versus-rentable warning, and named standards (ANSI/BOMA Z65.1, IPMS) for the step where a calculator stops and a surveyor starts.
Frequently asked questions
Net leasable area is the part of a building that can be rented to tenants: the total building area minus all common area such as lobbies, corridors, stairwells, lift shafts, shared restrooms and plant rooms. It is the area that can generate rent, stated for the whole building rather than for one suite.
Rentable area starts from a tenant’s usable area and adds back a pro-rata share of the building’s common areas through a load factor, so it is larger than the space the tenant actually occupies. Net leasable area, as calculated here, subtracts all common area from the total and never adds a share back, so the two figures answer different questions and should not be used interchangeably in a lease.
Common area is any space no single tenant leases exclusively: entrance lobbies, shared corridors, stairwells, lift shafts and lift lobbies, shared restrooms, concierge and security areas, and mechanical, electrical and janitorial rooms. Space inside one tenant’s own premises, including a private restroom or kitchen, is not common area.
No. Both inputs must be in the same unit, square feet or square meters, and the result is in that same unit. The calculator has no unit selector and performs no conversion, so converting one figure before entering it, or mixing units, will produce a wrong result with no warning.
No. Net leasable area is what remains after common area is subtracted, so it can equal the total only when the common area is zero. If the common area entered is larger than the total area, the calculator stops with the message that common area cannot exceed total area, which usually means the two figures were measured on different bases or in different units.
Usually not. Parking is normally measured, priced and leased separately from floor area, bay by bay or under its own licence terms. If a specific lease treats a parking level as lettable floor area, that choice should be stated in the lease rather than folded silently into the common area figure.
A certified surveyor or architect measuring under a named standard, such as ANSI/BOMA Z65.1 or the applicable IPMS basis, should set the figure a lease relies on. Remeasure after any change to the layout, a subdivision or merger of suites, or a conversion of common space to lettable space, because each of those changes one side of the subtraction.
No. Vacancy changes the rent a building collects, not the area it can let. An empty suite is still leasable area, so the net leasable area stays the same until the physical layout or the measurement basis changes.
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References
- Building Owners and Managers Association International (BOMA). ANSI/BOMA Z65.1-1996, Standard Method for Measuring Floor Area in Office Buildings (preview). Accessed October 22, 2026.
- UBC Sauder School of Business, Real Estate Division. BUSI 401 Review Guide: BOMA rentable and usable area calculations. Accessed October 22, 2026.
- Kreo Software. What Are BOMA Standards? A Guide to Accurate Area Measurement. Accessed October 22, 2026.
- Xmeasures. BOMA Office Standards: usable, floor common, building common and rentable area definitions. Accessed October 22, 2026.
- ORS Surveyors. Understanding International Property Measurement Standards (IPMS). Accessed October 22, 2026.
- McGees Property Brisbane. Understanding the Net Lettable Area: Key Insights for Property Owners. Accessed October 22, 2026.