Net Lettable Area (NLA) vs Gross Lettable Area (GLA): The $100,000 Detail Most Landlords & Tenants Get Wrong
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Let’s not sugarcoat it.
If you don’t know the difference between NLA and GLA, you’ve already lost the negotiation.
And I’m not saying that to scare you - I’m saying it to save you.
Because every day, I see investors, tenants and even some agents sign commercial leases based on the wrong assumptions.
They get told the building is “X square metres” and think that’s all there is to it.
But behind that number is a loaded weapon and depending on who’s holding it, it could be protecting your profit, or bleeding it dry.
So if you want to protect your cashflow, lease fairly and stop guessing your square meterage, keep reading.
What Is Net Lettable Area (NLA)?
Net Lettable Area (NLA) is the usable, exclusive floor area a tenant occupies in a building.
It’s typically used in office leases and is calculated from the internal face of the walls.
That means NLA only includes the actual space the tenant can work in, not shared amenities or plant areas.
- Toilets? - Not included
- Hallways? - Nope
- Plant rooms? - Forget it
- Kitchenette? Only if it's exclusive
This is the space that’s yours, and yours alone. Not shared. Not communal.
Just you, your team, your furniture and your daily hustle.
What NLA Includes:
- Internal usable space (measured wall to wall)
- Exclusive tea room (if not shared)
- Storage areas (if part of the tenancy)
- Columns, if they’re inside your exclusive area
What NLA Excludes:
- Toilets, lobbies and stairs
- Plant and equipment rooms
- Fire escapes, risers and lift wells
- Shared areas in multi-tenant buildings
- Public accessways
You can read more about Net Lettable Area (NLA) here.
What Is Gross Lettable Area (GLA)?
Now flip the coin.
Gross Lettable Area (GLA) is the total enclosed area of the tenancy - measured from the outside wall surfaces or the centreline of shared walls.
GLA is used in:
- Warehouses
- Industrial buildings
- Showrooms
- Large-format retail
In other words: it’s for bigger, less compartmentalised spaces.
GLA includes everything under the roof, whether you use it daily or not.
What GLA Includes:
- Toilets
- Plant rooms
- Stairs
- Storage
- Lift shafts
- Service ducts
- Covered loading docks
- Internal walls
What GLA Excludes:
- External areas
- Car parks
- Public foyers or common entrances
- Anything outside the enclosed footprint
So while NLA is about what you use, GLA is about what’s enclosed.
And that single difference?
It’s worth thousands per year in rent and hundreds of thousands in property valuation.
You can read more on Gross Lettable Area (GLA) here.
NLA vs GLA - Why the Difference Matters
Imagine this:
You sign a lease thinking you're getting 300m² of usable space.
But later you realise 50m² of that includes shared toilets, a stairwell and a plant room.
You're paying for 300m².
You're only using 250m².
Let that sink in.
Now multiply that by your rate:
300m² @ $500/m² = $150,000 per year
But for the space you're actually using?
250m² = $125,000
That’s $25,000 every year you’re overpaying because you didn’t confirm whether your lease used NLA or GLA.
Tip: Always Ask - “Is this NLA or GLA?”
If the agent, landlord or broker can’t answer?
Red flag.
You’re either being misled, or they don’t know and either one means you’re exposed.
Who Sets the Rules? The Property Council of Australia (PCA)
In Australia, there’s no guessing game when it comes to these measurements.
The Property Council of Australia (PCA) has published a gold-standard document:
This guide sets out exactly how to measure NLA and GLA across all property types and any lease worth signing should be based on these.
The PCA Standard Ensures:
Consistency - Everyone’s working from the same rules
Transparency - No creative square metres
Comparability - You can compare spaces fairly
Trust - You know exactly what you’re paying for
Common Mistakes That Cost Thousands
Mistake #1: Using Building Plans Instead of “As-Built” Surveys
Architectural drawings lie.
What gets built can change and using outdated plans can add or subtract 10–15m² without you knowing.
Mistake #2: Confusing GLA with GFA
GLA (Gross Lettable Area) is for leasing.
GFA (Gross Floor Area) is for planning and development.
Using GFA to price rent? You’ll overpay for space that’s not even usable.
Mistake #3: Not Recalculating After Fit-Outs or Mezzanines
Your tenant adds a mezzanine?
That can impact your NLA and your rent potential.
But if it’s not updated in the lease, you’re leaving money on the table.
Scenario: The 1,100m² Warehouse that Was Really 1,045m²
A client bought an industrial property leased at $120/m² GLA.
The previous agent had it listed as 1,100m².
We conducted a PCA-compliant measurement. Actual GLA? 1,045m².
That’s 55m² overstated - which at $120/m², equated to $6,600/year in inflated value.
Over the 5-year lease term?
$33,000 miscalculated into the valuation.
What Happens If You Get It Wrong?
- You overpay on rent
- Your asset is over or undervalued
- Your outgoings are misallocated
- You inherit a dispute you didn’t cause
- You lose negotiating power
The kicker?
Most of these issues are completely preventable with proper documentation and due diligence.
Which Measurement Should You Use?
|
Property Type |
Use NLA or GLA? |
|
Office Suites |
NLA |
|
Warehouses |
GLA |
|
Showrooms |
GLA |
|
Industrial Units |
GLA |
|
Retail (large format) |
GLA |
|
Multi-tenant Commercial |
NLA |
Rule of thumb:
- Use NLA for precision space (offices).
- Use GLA for total enclosed areas (industrial, retail).
How to Calculate NLA and GLA (The Easy Way)
Net Lettable Area (NLA) Formula:
Measure from internal finished surfaces of walls
Exclude:
- Toilets
- Plant rooms
- Public corridors
- Fire escapes
Gross Lettable Area (GLA) Formula:
Measure from external faces of walls or centreline of shared walls
Include:
- All enclosed structural features
- Toilets, stairs, plant, loading docks
How to Protect Yourself (Landlords & Tenants)
Insist on a PCA-Compliant Survey
Get a surveyor to measure the space based on the Property Council’s Method of Measurement.
Don’t rely on the agent’s brochure.
Reference Measurement Method in the Lease
Spell it out:
“Lettable area calculated in accordance with PCA Method of Measurement (current edition).”
This removes any grey area later.
Keep a Floor Plan with Area Marked
Ensure your lease has an appendix with the floorplan, measurements and version history.
Review Measurements Post-Construction or Fit-Out
Buildings change. So should the measurements.
Don’t Just “Trust the Brochure”
Always verify.
Because every square metre is either a dollar gained or lost.
Lease Smarter, Not Louder
At the end of the day, this isn’t about being pedantic.
It’s about being profitable.
Whether you’re a landlord looking to maximise rent… or a tenant making sure you don’t pay for toilets you don’t use - NLA and GLA are the foundation of your financial success.
Get it wrong and you’ll bleed cash silently over years.
Get it right and you’ve just added hundreds of thousands in real value to your investment.
So next time someone hands you a lease that says “300m²”?
Your first question should be:
“Is that Net Lettable Area or Gross Lettable Area?”
Because if they can’t answer it…
You shouldn’t sign it.