Gross floor area (GFA) and built-up area (BUA) are two different ways of measuring a building, and mixing them up can distort price comparisons, plot feasibility and permit planning. Buyers, investors and developers should know which figure a listing, contract or approval uses before making any decision.
Quick answer: GFA (gross floor area) is the enclosed floor area authorities use to apply planning limits like FAR. BUA (built-up area) is the total constructed area quoted in sales and is often larger because it can include balconies. Definitions vary, so check your contract.
What is gross floor area (GFA)?
Gross floor area is the measurement planning authorities use to control how much can be built on a plot. The Dubai Building Code 2021 describes it as the measurement used by planning authorities in Dubai to define floor area ratio (FAR), where FAR is the ratio of GFA to plot area.
In practice, GFA usually means the total enclosed floor area of a building, added up across all levels and measured at the external walls. Which spaces count, such as parking, plant rooms, balconies or open terraces, depends on the authority's rules and the project's approvals. Always confirm the treatment for the specific plot.
What is GFA in construction and real estate?
In construction, GFA is a planning and cost benchmark. In real estate, it is the figure that shows how much floor space a project is allowed or approved to have. It is used in four main ways:
- Permits and zoning: the approved GFA must stay within the limit set by the plot's FAR.
- Feasibility: developers and investors estimate how many units or how much sellable space a plot can support.
- Cost benchmarking: teams often compare construction cost per sq m of GFA across projects.
- Design efficiency: comparing GFA with net sellable or lettable area shows how much of a building is usable.
Some countries use other terms, such as gross internal area or gross external area under international measuring standards. When reading overseas reports, check which basis they use.
What is built-up area (BUA)?
Built-up area is the total constructed area. The Dubai Building Code 2021 defines it as the total constructed area in a building or in the structures on the plot.
In Dubai listings and sales contracts, BUA is the figure most buyers see. For an apartment it is commonly the unit's usable internal area, plus wall and structural thickness, plus balconies or terraces. Some developers also add a share of common areas, so the basis can differ between projects.
Typical BUA formula (apartment): BUA = net internal area + walls and structure + balcony or terrace [+ share of common areas, if the contract says so].
GFA vs BUA: what is the difference?
GFA measures the enclosed floor area for planning control, while BUA measures everything constructed, and is the number most often used to market a property. Here is how they compare:
| Aspect | GFA (gross floor area) | BUA (built-up area) | Net / usable area |
|---|---|---|---|
| What it measures | Enclosed floor area counted for planning | Total constructed area | Space you can actually use inside |
| Main purpose | FAR, permits, compliance | Sales, leasing, registration | Comparing real living space |
| Main users | Authorities, developers, architects | Buyers, sellers, brokers | Buyers, valuers, designers |
| Balconies and terraces | Depends on authority rules | Usually included | Excluded |
| Walls and structure | Usually included | Included | Excluded |
| Which is larger? | Varies | Often the largest for a unit | Smallest |
Because the definitions overlap, BUA is often larger than net area, but it is not always larger than GFA for a whole building. Compare numbers only when they are measured on the same basis.
What is net area, and why does it matter?
Net (usable) area is the space inside the unit that you can actually use, excluding walls and structure. It tells you how efficient a layout is.
Efficiency ratio (%) = net usable area ÷ BUA × 100
Illustrative example (hypothetical figures): a one-bedroom apartment has 60 sq m of net internal area, 6 sq m of walls and structure, and an 8 sq m balcony. Its BUA is 74 sq m, so its efficiency ratio is 81.1 per cent. Now see how the price per sq ft changes with the basis, for a Dh1.2 million price:
| Basis | Area | Price per sq ft |
|---|---|---|
| BUA | 74 sq m (about 797 sq ft) | about Dh1,507 |
| Net usable area | 60 sq m (about 646 sq ft) | about Dh1,858 |
The same apartment looks cheaper or dearer by about 23 per cent depending on the area used. That is why you should compare apartments on the same basis.
How do you calculate FAR and permitted GFA?
FAR is the ratio of gross floor area to plot area, so permitted GFA equals plot area multiplied by FAR.
FAR = GFA ÷ plot area | Permitted GFA = plot area × FAR
Illustrative example: a 1,000 sq m plot with a permitted FAR of 3.0 allows up to 3,000 sq m of GFA. That could be ten floors of 300 sq m each, or six floors of 500 sq m each. Both use the same GFA but a different footprint.
Two cautions apply:
- FAR is not plot coverage. Plot coverage measures only the ground-floor footprint as a share of the plot.
- Do not price a plot on bonus FAR unless the authority has confirmed it in writing.
The 3-Number Area Check
For any property, ask for three numbers and the basis of each: GFA (for plots and whole buildings), BUA (the figure in the contract) and net usable area (what you actually get). If a seller gives only one, you cannot judge value properly.
Why does the difference matter?
- Buyers: price per sq ft can change by 20 per cent or more depending on the area basis, and you may overpay if you compare unlike figures.
- Investors: rental yield and resale value depend on usable space, not just the headline BUA.
- Developers and plot buyers: exceeding the permitted GFA can lead to non-compliance, redesign and delays.
- Valuers and lenders: valuations and loan decisions rely on measured, approved areas.
How do you check the area before you buy?
- Ask the seller or developer which area basis the quoted figure uses.
- Compare it with the sales and purchase agreement (SPA), title deed or Oqood record for off-plan units.
- Check the approved floor plan and any GFA or BUA breakdown.
- Calculate the efficiency ratio and the price per sq ft on both BUA and net area.
- For plots, confirm the FAR, permitted GFA and any exclusions in writing with the relevant authority or master developer.
- Consider an independent surveyor's measurement or valuation for high-value purchases.
Common mistakes
- Comparing BUA from one project with net area from another.
- Using BUA to calculate FAR.
- Assuming balconies and parking count the same way in every project.
- Buying a plot without confirming its permitted GFA.
- Relying on an advertisement instead of the contract and approved plans.
What this means for you
Before your next property decision, write down the three numbers (GFA, BUA and net area), the basis of each and where it is documented. If you are buying a plot, make GFA and FAR your first questions. If you are buying a unit, make net area and price per sq ft on a like-for-like basis your first checks.
Conclusion
GFA tells you how much a plot or building is allowed and approved to hold. BUA tells you how much was constructed and how the property is usually sold. Net area tells you how much you can really use. Ask for all three, confirm the basis in writing, and compare properties like for like.
Frequently asked questions
What does GFA mean?
GFA stands for gross floor area. It is the total enclosed floor area of a building across all levels, used by planning authorities to apply limits such as floor area ratio. Which spaces count can vary by authority and project, so check the approved plans.
What is GFA in construction?
In construction, GFA is the planning and cost benchmark for a building's enclosed floor area. It is used for permits, zoning limits, feasibility studies and comparing construction cost per square metre across projects. Its exact inclusions follow local authority rules.
Is BUA bigger than GFA?
Not always. BUA often looks larger for a unit because it can include balconies and terraces, but GFA for a whole building can include shared enclosed areas that a unit's BUA does not. Compare figures only when both are measured on the same basis.
How do you calculate gross floor area?
Add up the enclosed floor area of every level, measured as the authority defines it, usually at the external walls. For a plot, permitted GFA equals plot area multiplied by the permitted floor area ratio. Confirm exclusions with the authority.
What is the difference between GFA and FAR?
GFA is an area, measured in square metres or square feet. FAR is a ratio: GFA divided by plot area. A FAR of 3.0 on a 1,000 sq m plot allows up to 3,000 sq m of gross floor area.
Which area should I use to compare property prices?
Compare price per sq ft on the same basis across all properties, ideally on both BUA and net usable area. Net area shows the space you can actually use, while BUA matches the contract. Always check which figure each listing quotes.
