Carpet Area vs Built-Up vs Super Built-Up: What Bengaluru Buyers Pay For
The size on the brochure is not the space you use. Here is the difference between carpet, built-up and super built-up area, what the loading factor costs you, and how RERA lets Bengaluru buyers compare flats fairly.
A Bengaluru buyer proudly told friends she had bought a 1,200 square foot flat, then measured the rooms after moving in and found barely 850 square feet of space she could actually use. She had not been cheated. She had simply paid on the super built up area, the saleable figure that folds in her share of lobbies, lifts and corridors, while the space inside her own walls, the carpet area, was a third smaller. The gap between what you buy and what you use has a name, the loading factor, and every Bengaluru buyer should understand it before comparing prices.
The short answer. Carpet area is the net usable floor space within your walls; built up area adds the walls and balcony; and super built up, or saleable, area adds your share of common spaces such as lobbies and lifts. Carpet area is typically only 65 to 75 percent of the super built up area, a loading factor of roughly 25 to 35 percent. Under RERA, developers must sell and disclose on carpet area, not super built up, which is the buyer's key protection. The trade off to grasp is that a low per square foot price quoted on super built up area can be less generous than a higher price quoted on carpet area.
Area definitions are where price comparisons quietly go wrong, because two flats quoted on different bases are not comparable at all. This guide explains the three measures, what the loading factor really costs you, how RERA protects buyers, and how to compare flats on a like for like basis.
What is carpet area under RERA?
Carpet area under RERA is the net usable floor area within the walls of the apartment, the space you can actually lay a carpet on. It includes the living room, bedrooms, kitchen, bathrooms and the internal partition walls, but excludes the external walls, service shafts, the exclusive balcony or verandah, and any exclusive open terrace. In plain terms it is the real, usable footprint of your home, and it is the figure RERA made the standard for selling residential property.
This definition matters because it is precise and buyer friendly. By fixing carpet area as a net usable measure and requiring developers to disclose it, RERA gave buyers a consistent number to compare and to hold a developer to. When you know the carpet area, you know how much home you are genuinely getting, independent of how the common areas are apportioned or how the marketing frames the size.
How do built up and super built up area differ from carpet area?
Built up area is your carpet area plus the walls and balcony, while super built up area adds your proportionate share of the building's common spaces. Built up area, taking in the internal and external walls and the balcony or utility, is usually 10 to 20 percent larger than the carpet area. Super built up area, also called the saleable area, goes further and loads in a share of lobbies, lifts, staircases, corridors and amenities like a clubhouse.
The result is a hierarchy: carpet area is the smallest and most useful, built up is larger, and super built up is the largest and the one traditionally used to quote a price. Because super built up includes space you share rather than occupy, a flat can be advertised at an impressive size while the usable area inside your walls is considerably smaller. Knowing which measure a price refers to is the difference between a fair comparison and a misleading one.
What is the loading factor and what does it cost me?
The loading factor is the extra percentage added to your carpet area to arrive at the super built up area, and it typically runs from about 25 to 35 percent. Put the other way, carpet area is usually only 65 to 75 percent of the super built up figure. So on a flat sold as 1,200 super built up square feet at a 35 percent loading, the carpet area, the space you actually use, is closer to 850 to 900 square feet.
This is why loading matters when you compare prices. A lower per square foot rate quoted on a high loading super built up area can deliver less usable space than a higher rate quoted on carpet area. The honest comparison is always carpet to carpet. When a developer or agent quotes a size, ask whether it is carpet or super built up, and ask for the loading factor, so you can translate the marketing figure into the home you will live in.
How does RERA protect buyers on area?
RERA protects buyers by making carpet area the standard unit for selling residential property and requiring developers to clearly disclose it. Before RERA, developers routinely priced on super built up area, which let generous loading inflate the headline size. By fixing carpet area as the basis, RERA gave buyers a defined, comparable measure and reduced the room for area to be presented misleadingly.
The protection also extends to what is delivered. Under RERA a shortfall between the carpet area promised in the agreement and what is actually handed over can entitle the buyer to a remedy, so it is worth verifying the delivered carpet area against the agreement rather than assuming it matches. For verifying the project behind the flat, see our guide to checking a project on RERA Karnataka, and for the cost you pay to register it, our guide to Bengaluru stamp duty and registration charges.
How should I compare flats on area?
Compare flats on carpet area, always, and translate every quoted figure back to carpet before you judge value. If one flat is quoted on carpet and another on super built up, they are not comparable until you convert them to the same basis using the loading factor. A flat that looks larger or cheaper on super built up may offer less usable space than a rival quoted honestly on carpet.
Build a simple habit: for every flat, note the carpet area, the super built up area and the loading factor, then compare the price per carpet square foot across your options. This strips away the marketing and shows what each home genuinely costs for the space you will use. Buyers who do this consistently avoid overpaying for loading and choose homes on their real, usable size. It also sharpens your negotiation, because once you can state the price per carpet square foot, a seller can no longer hide a steep loading behind an attractive headline rate.
What area mistakes do Bengaluru buyers make?
The common mistakes are comparing flats quoted on different bases, ignoring the loading factor, and assuming the advertised size is usable space. Each distorts value. Comparing a carpet quote against a super built up quote makes the smaller looking flat seem worse when it may be better. Ignoring loading hides how much you pay for shared space. And treating the headline size as usable leads to the shock of a much smaller home than expected.
Avoiding them is simple once the terms are clear. Ask whether every quoted size is carpet or super built up, note the loading factor, compare on carpet area, and verify the carpet area stated in your agreement. Because RERA requires disclosure on carpet area, the information is there to be used. Buyers who insist on it buy the home they think they are buying, at a price they can genuinely compare.
Carpet, built up and super built up compared
| Measure | What it includes | Note for buyers |
|---|---|---|
| Carpet area | Net usable floor area within your walls | The space you actually use, and RERA's selling basis |
| Built up area | Carpet plus walls and balcony | Usually 10 to 20 percent more than carpet |
| Super built up area | Carpet plus a share of common spaces | The saleable figure often used to quote a price |
| Loading factor | The percentage added to carpet | Typically 25 to 35 percent |
| RERA rule | Sell and disclose on carpet area | Developers must state the carpet area |
An area checklist for Bengaluru buyers
- Ask whether every quoted size is carpet area or super built up area.
- Note the RERA carpet area, the space you will actually use.
- Ask for the loading factor to see the gap between carpet and super built up.
- Convert every flat to carpet area before comparing prices.
- Compare the price per carpet square foot across your options.
- Check that the carpet area is clearly stated in your agreement.
- Verify the delivered carpet area against the agreement on possession.
Frequently asked questions
What is carpet area under RERA?
Carpet area under RERA is the net usable floor area within the walls of an apartment, including rooms and internal partition walls but excluding external walls, service shafts, the exclusive balcony and any exclusive open terrace. It is the real usable space of your home, and RERA made it the standard unit for selling residential property.
What is the difference between carpet area and super built up area?
Carpet area is the usable space within your walls, while super built up area adds your proportionate share of common spaces such as lobbies, lifts and corridors. Carpet area is typically only 65 to 75 percent of the super built up figure, so a flat sold on super built up area offers less usable space than its headline size suggests.
What is the loading factor?
The loading factor is the percentage added to your carpet area to reach the super built up area, usually about 25 to 35 percent. It represents the share of common areas loaded onto your flat. A higher loading means more of the quoted size is shared space, so always compare flats on carpet area rather than on the loaded super built up figure.
How does RERA protect me on area?
RERA requires developers to sell and disclose residential property on carpet area rather than super built up area, giving buyers a defined, comparable measure. It also provides recourse if the delivered carpet area falls short of what the agreement promised, so it is worth verifying the actual carpet area against your agreement when you take possession.
Last updated 14 August 2026. PropNewz Team.
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