When you start looking at flats, you will hear three different area numbers for the same home: carpet, built-up and super built-up. They can differ a lot. Knowing what each one measures stops you from comparing apples with oranges, and helps you understand what you are actually paying for.
The three areas, from smallest to largest
| Area | What it measures | Who defines it |
|---|---|---|
| Carpet area | The usable floor inside your flat, including internal partition walls, but not external walls, service shafts, your exclusive balcony or open terrace | Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 |
| Built-up (plinth) area | The covered area measured to the outer face of the walls, so wall thickness is included | National Building Code of India; IS 3861 sets the measuring method |
| Super built-up area | Built-up area plus a share of common spaces like lobbies, stairs and lift areas | No law or standard defines it |
For the same flat, carpet is always the smallest and super built-up the largest.
Carpet area: the one the law protects
RERA defines carpet area and requires it in your agreement for sale. That is why it is the safest number to compare. If one project quotes carpet and another quotes super built-up, you cannot fairly compare the two until you have both carpet figures.
Plinth or built-up area: the one the approvals use
Plinth area is measured at floor level to the outside face of the enclosing walls. The National Building Code of India defines it, and the Indian Standard IS 3861 explains exactly what to count. These become binding through local building bye-laws and the sanctioned plan.
You do not buy on plinth area, but it matters behind the scenes:
- Floor area ratio. How much can be built on a plot is checked using covered area.
- Bye-law checks. Setbacks and ground coverage are measured on the covered footprint.
- Approval fees. Authorities often charge on covered area.
- Property tax. In Karnataka, local bodies using the unit-area method assess tax on built-up area.
Super built-up area: handle with care
No law defines super built-up area, and there is no standard way to calculate it. Different builders may add common spaces in different ways. It is not wrong to mention it, but never rely on it alone.
A simple example
Imagine a flat quoted at 1,300 square feet super built-up, with a carpet area of 975 square feet. The loading is 1,300 − 975 = 325 square feet, which is 325 ÷ 975, about 33 per cent of the carpet area. Another flat quoted at 1,250 super built-up might actually have more carpet area if its loading is lower. Only the carpet figures tell you which home is roomier inside.
These numbers are only for illustration; always use the figures in the actual agreement.
Where each number should appear
| Document | Area you should see |
|---|---|
| Agreement for sale | Carpet area, as defined by RERA |
| Sanctioned plan | Plinth area, floor by floor |
| Property tax assessment | Built-up area |
| Brochure or ad | Any of the three. Check which one |
Section 19(1) of RERA lets you obtain the sanctioned plans and specifications. That means you can compare the plan with the carpet area in your agreement and see whether they describe the same home.
Four questions to ask every time
- Is this figure carpet, built-up or super built-up?
- What is the carpet area of this exact flat, as it will appear in the agreement?
- May I see the sanctioned plan for this floor?
- If two figures disagree, which document governs? The answer should be the agreement and the approved plan.
Price per square foot: the trap in the ad
Most ads quote a rate per square foot. The trap is that the rate may be per super built-up foot, which makes it look lower than it really is for the space you can use.
Illustrative figures only. Compare two flats:
| Flat A | Flat B | |
|---|---|---|
| Quoted area (super built-up) | 1,300 sq ft | 1,250 sq ft |
| Quoted rate | ₹6,000 per sq ft | ₹6,200 per sq ft |
| Total price | ₹78,00,000 | ₹77,50,000 |
| Carpet area | 975 sq ft | 1,000 sq ft |
| Price per carpet sq ft | ₹8,000 | ₹7,750 |
Flat A looks cheaper per foot in the ad. Flat B is actually cheaper per foot you can use, and it is roomier inside. Divide the total price by the carpet area and the picture becomes honest.
What is inside carpet area, and what is not
Read section 2(k) of RERA once and you will remember it. In plain words:
- Included: the floor of every room, the kitchen, bathrooms, passages inside the flat, and the area under internal partition walls.
- Not included: the external walls, areas under service shafts, your exclusive balcony or verandah, and your exclusive open terrace.
Balconies are not lost. A good agreement lists them separately, with their own area. Ask for that figure too, because a large balcony is useful space even though it is not carpet.
How to check the carpet area yourself
- Get the unit plan for your exact flat, with room dimensions.
- Multiply length by breadth for each room, measured wall face to wall face. A bedroom of 11 ft × 12 ft is 132 sq ft.
- Add the rooms, bathrooms and passages. Your total should be close to the carpet area in the agreement, after adding the small area under internal walls.
- At handover, measure again with a tape or laser meter. Plastering and finishes reduce space slightly, so expect small differences, not large ones.
Section 14 of RERA says the promoter must build to the sanctioned plans and specifications. Changes need your written consent, apart from minor additions or alterations the Act allows. If the carpet area at handover is clearly less than agreed, raise it in writing.
Common mistakes
- Comparing different area types. Carpet against super built-up tells you nothing.
- Assuming loading is the same everywhere. It varies by building design, amenities and the number of flats sharing them.
- Paying for a figure that is not in the agreement. If the cost sheet uses super built-up, ask for the carpet area and the per-carpet-foot price in writing.
- Forgetting the balcony area. It should be stated separately, so you know what you are getting.
- Not measuring at handover. Do it before you sign the possession letter.
Why loading is not always bad
Higher loading can mean wider corridors, a bigger lobby or a clubhouse. Lower loading can mean more usable space for your money. Neither is right or wrong. What matters is that you know how much of the price buys your own floor and how much buys shared spaces you will use.
Common area numbers you will hear, translated
Sales teams sometimes mention more terms. Here is what they usually mean, so you can ask the right follow-up:
- Saleable area. Usually another name for super built-up area. Ask for the carpet area.
- RERA carpet. Carpet area as defined in section 2(k). This is the figure you want.
- Usable area. Not a defined term. It may or may not include balconies. Ask what it includes.
Your area checklist
- Carpet area of this exact flat, in writing
- Balcony and terrace areas listed separately
- Price divided by carpet area worked out
- Unit plan with room dimensions received
- Sanctioned plan seen for your floor
- Measurement planned before possession
New to all this? Our first home guide explains these terms and the rest of the buying process step by step.